Copyright
E. A. (Edward Albert) Sharpey-Schäfer.

Text-book of physiology; (Volume v.1) online

. (page 49 of 147)
Online LibraryE. A. (Edward Albert) Sharpey-SchäferText-book of physiology; (Volume v.1) → online text (page 49 of 147)
Font size
QR-code for this ebook


quantity ; the colour disappears on adding mercuric chloride. This test is
difficidt to obtain. (2) A filter paper is dipped in a loeak solution of ferric
chloride, containing a trace of hydrochloric acid, and then allowed to dry, when
it should have only a faint amber colour. On such test paper a drop of saliva
produces a reddish stain. ^ (3) Filter paper is impregnated with tincture of
guaiacum, and then drawn through a solution of 0'05 per cent, copper sulphate.
On such paper, saliva containing sulphocyanate causes a blue stain.'^ (4) Saliva
is treated with iodic acid, when iodine is set free ; this in turn is treated with
starch paste, when the blue compound of starch and iodine appears. This is
said to be an exceedingly delicate reaction, showing a most minute trace of
sulphocyanate, and not being produced by saliva free from sulphocyanate,^ but
iodic acid is an exceedingly unstable compound, and the latter statement is
questionable.

Sulphocyanate is often absent in human saliva. Some authors state that
it is found in dog's saliva, others that it is not ; the explanation may be that
its presence in dog's saliva is also not constant. It is said to be absent in the
saliva of the horse, ox, sheep, goat, and pig.^ Leared '^^ found that sulpho-

1 See Maly, Hermann's "Handbuch," Bd. v. (2), S. 8.

^ The older analysts were accustomed to ]3roportion the bases and acids, on the
supposition that as much as possible of the so-called strongest acid was combined with the
strongest base. We now know that the acids and bases are distributed according to definite
laws, and no longer speak of so much chloride, for example, as existing in a complex
mixture, but state separately so much sodium and so much chlorine, etc.

3 " Biologic," 1814, Bd. iv. S. 330.

* " Die Verdauung nach Versuchen," Bd. i. S. 8.

s See Maly, Hermann's "Handbuch," Bd. v. (2), S. 10, 14.

® Gscheidlen, Jahresb. il. d. Fortsclir. d. Thier-Chem., Wiesbaden, 1874, Bd. iv. S. 91.

7 Bottger, ibid., 1872, Bd. ii. S. 204.

8 Solera, ibid., 1877, Bd. vii. S. 256 ; 1878, Bd. viii. S. 235.

^ Ellenberger and Hofmeister, " Vergleich. Phys. d. Haustiere," Berlin, 1890, S.
495.

^" Proc. Roy. Soc. London, 1870, vol. xviii. p. 16.



346 CHEMISTR Y OF THE DIGESTIVE PROCESSES.

cyanate was present in the blood and urine as Avell as in the saHva.
Gscheidlen ^ and Munk ^ have also found it in urine.

An exalted importance has been given to the sulphocyanate in saliva,
from its supposed origin from proteid, and from its assumed value as an
indicator of the rate of proteid metabolism. Sulphocyanic acid has a
similar constitution to cyanic acid, an atom of sulphur merely replacing an
atom of oxygen, and the ammonium salt of sulphocyanic acid undergoes a
similar decomposition to that of cyanic acid, yielding sulpho-urea instead
of urea, thus : —

Oxygen compounds— CK OH; CN.O.NH^; CO.(NH2)2
(cyanic acid) (ammonium (urea)

cyanate)

Sulphur compounds— CKSH ; CKS.l^H^ ; CS.(NH2)2
(sulpliocyanic (ammonium (sulpho-urea)
acid) sulphocyanate)

From this relationship, from the presence of sulphur in its molecule, and
from its presence in the urine, and in traces in the blood, it is probable that
the sulphocyanate of the saliva is a product of proteid metabolism. Fenwick ^
has investigated the variation in the sulphocyanate of the saliva, especially in
relation to the variations in the nutrition of the body under pathological
conditions. He states that the amount of sulphocyanate bears a relationship
to the amount of sulphiu' (as taurocholates) in the bile, and that when the
bile is diverted from the alimentary canal the sulphocyanate of the saliva
disappears. That it would be dangerous to take the amount of sulphocyanate
as any gauge of the amount of proteid metabolism, is shown by its complete
absence in many species of animals, and in many individuals where it is
normally present in a species ; this does not make any the less probable
the statement that in those individuals in which sulphocyanate is present its
quantity should vary Avith the activity of proteid metabolism.

Saliva also contains traces of nitrites,"^ which may be demonstrated by
diluting saliva with five times its volume of water, making acid with sul-
phuric acid and adding a solution of metadiamido-benzol, when an intense
yellow colour is produced. In this way Griess estimated colorimetrically
the amount of nitrite in saliva at 1-10 mgrms. per litre. Minute traces of
ammonia may also be shown to be present in saliva by the addition of Nessler's
reagent.^

Gases of the saliva. — The saliva holds considerable volumes of gas in
solution or in chemical combination. In human parotid saliva, Kiilz ^ found
in 100 vols, of saliva, of oxygen, 1"46 vols.; of nitrogen, 2-8 vols.; and of
carbon-dioxide 66 "7 vols., of which latter 62 vols, were in chemical
combination. In submaxillary saliva of the dog, obtained by stimulating
the chorda tympani, Pfliiger'' found 0'5-0'8 vols, of oxygen, O'9-l'O vols.
of nitrogen, and 64'73-85'13 vols, of carbon-dioxide, most of the latter
being chemically combined. These figures are interesting, both because of the
large amount of carbon-dioxide present, and the fact that the oxygen exceeds
the amount dissolved by blood plasma.

^ Arch./, d. cjes. Physiol., Bonn, 1877, Bd. xiv. S. 401.

2 Virchrnv's Archiv, 1877, Bd. Ixix. S. 354.

^ Fenwick, "The Saliva as a Test for Functional Disorders of the Liver," London, 1889.

■* Schcinbein, Journ. f. 2Jrakt. C'hem., Leipzig, Bd. Ixxxvi. S. 151 ; Schaer, Ztsdir.f. Biol.,
Mlinchen, Bd. vi. S. 467 ; Griess, Bcr. d. dcutsch. chevi. Gesellsch., Berlin, Bd. ii. S. 624.

5 Maly, Hermann's "Handbuch," Bd. v. (2), S. 8. See also W. Sticker, Miinchen.
mcd. Wchnschr., 1896, Bd. xliii. ISTos. 42-43.

« Ztsclir. f. Biol, Miinchen, 1887, Bd. xxiii. S. 321.

'' Arch./, d. ges. Physiol., Bonn, 1868, Bd. i. S. 686.



ANALYSES OF SALIVA.



347



Tables of Analyses of Saliva.

TABLE I.

Submaxillary Saliva.





I.


11.


III.


IV.






Gases.




I.


II.


Water

Total Solids .
{a) Organic .
(b) Inorganic

1. Soluble

2. Insoluble


991-45

8-55
2-89
5-66
4-50
1-16


996-04

3-96
1-51

2-45


994-4

5-6

1-75
3-85
3-59
0-26


991-14

8-86
3-53
5-33
5-27
0-06


K,SO^ 0-209'

KCl 0-940
NaCl 1-546
NaoCOo 0-902
CaCOg 0-150
Ca3(P0J, 0-113 J


O


CO„freel9-3
C0„ com-
bined 29-9
Nitrogen 0-7

Oxygen 0-4


22-5

42-5
0-8

0-6



Analyses I. and II. are of dog's saliva, by Bidder and Schmidt.^ Analysis
III. is by Herter.2 Analysis lY. is of cow's saliva.^ The ash analysis is by
Herter.'* The gas analyses are of dog's saliva by Pfliiger.^



TABLE II.
Parotid Saliva.





I.


II.


III.


IV.


V.


VI.


VII.


Water

Total Solids
'{a) Organic
(&) Inorganic .

1. Soluble .

2. Insoluble


985-4-983-7

14-6-16-3

9-0

5-3


993-16

6-84
3-44-
3-40


995-3
4-7
1-4
3-3

2-1
1-2


991-5-993-8
8-47-6-1
1-53
6-93
6-25
0-68


990-00

10-0

2-06-6-0

4-8-8-73


990-7
9-3
0-44
8-82
8-72
0-10


869-0

11-0

1-0

10-0

10-0.

Traces



This table has been compiled from Maly.<5 I. and II. are analyses of
human parotid saliva, by Mitscherlich and Hoppe-Seyler respectively. The
former states the amount of the sulphocyanate in his sample at 0-3 per thousand.
III. and IV. are of dog's parotid saliva, by Jacubowitsch and Herter respect-
ively ; that given as soluble is set doAvn by them as CaCOg. Y. is of horse's



parotid saliva by Lehmann.
respectively, by Lassaigne.



YI. and YII. of the coav's and ram's parotid saliva



TABLE III.
Submaxillary, Parotid, and Sublingual Saliva.





Submaxillarjr Saliva.


Parotid Saliva.


Sublingual Saliva.


I.


11.


III.


IV.


I.


II.


III.


I.


11.


III.


IV.


Water .


987-7


988-7


983-2


987-4


991-4


992-6


992-6


978-8


984-7 ■


986-3


957-2


Total Solids


12-3


11-3


16-8


12-5


8-6


7-4


8-1


21-2


15-3


13-7


12-8


(a) Organic




6-6


10-2


6-2




0-6


4-0




1-9


4-3


3-4


(6) Inorganic .




4-7


6-6


6-4




6-8


4-1




13-4


9-4


9-4


1. Soluble .


5-6


4-3


5-8


6-0


5-6


6-4


3-6


11 -0


12-7


9-0


9-3


2. Insoluble .




0-42


0-73


0-42




0-45


0-54




0-68


0-44


0-17


Alkalinity —
























(as Na.jC03) .


1-6


1-7


1-1




1-9


1-7


1-7


...








Chlorides —
























(as NaCl)


3-35


1-5


3-29




2-39


0-78


0-85


7-06


10-8


8-14





1 Maly, Hermann's "Handbucli," Bd. v. (2), S. 19.

2 Hoppo-Seyler, " Physiol. Chem.," Bd. ii. S. 191.

^ Lassaigne, cited by Maly, loo. cit. "* Loc. cit. ^ Maly, loc. cit.

"Hermann's "Handbucb," Bd. v. (2), S. 16, 17; Hoppe-Seyler, "Physiol. Chem.,"
Bd. ii. S. 198, 199.



348



CHEMISTRY OF THE DIGESTIVE PROCESSES.



This table shows the results obtained by Werther ^ in four experiments on
dogs, in which all three kinds of saliva were collected and analysed. The results
have been placed in a similar form to that of the other tables, for ease of com-
parison. It should be observed that the sublingual saliva was barely alkaline
in all four experiments, while the submaxillary saliva was only so in one
experiment; that the sublingual saliva contains in spite of its viscidity no
more organic matter than the others, while it does contain much more
chlorides. Human sublingual saliva has never been obtained in sufficient
quantity for analysis.

TABLE IV.

Buccal Mucus.

Water 990-02

Total solids 9-98

Organic matter —

(«) Soluble in alcohol 1-67

(&) Insoluble in alcohol ....... 2'18

Inorganic salts —

Chiefly chloride and phosphate of sodium . . . 6 '13

From Bidder and Schmidt, quoted by Maly.^

TABLE V.
Mixed Saliva.





I.


II.


III.


IV.


V.


VI.


VII.


Water


992-9


995-1 ■


994-1


988-3


994-7


994-2


989-6


Total solids ....


7-1


4-84


5-9


11-7


5-3


5-8


10-3


Suspended solids (epithe-
















lium, mucus, etc.) .


1-4


1-62


2-13






2-2




Soluble organic matter


3-8


1-34


1-42




3-27


1-4


3-58


Potassium sulphocyanide .




0-06


0-10






0-04




Inorganic salts .


1-9


1-82


2-19




1-03


2-2


6-79



Ash of Mixed Saliva.





Human.


Dog.


Total solids (in 1000 parts






of saliva)


1-82


6-79


Phosphoric acid .


0-51\


0-82


Soda ....


0-43J


Lime ....

Magnesia


0-03)
0-01/


0-15


Alkaline chlorides


0-84


5-82



Analyses I. to VI. are of human saliva by Berzelius, JacuboAvitsch, Frerichs,
Tiedemann and Gmelin, Herter, and Hammerbacher respectively. Analysis
VII. is of dog's saliva by Schmidt. The table is taken from Maly,^ except
Analysis VI., which is from Hammerbacher.'* The analyses of ash are by
Jacubowitsch.'^ In 1000 parts of the ash of mixed human saliva, Hammer-
bacher 6 found 457-2 of K,0, 95-9 of Na.,0, 50-11 of Fe.Og, 1-55 of MgO,
63-8 of SO3, 188-48 of P.Or. and 183-5 of chlorine.



^ Arch. f. cl. ges. Plbijsiol., Bonn, 1886, Bd. xxxviii. S.
2 Hermann's "Handbuch," Bd. v. (2), S. 20.
-* Ztschr. f. physiol. C'hem. , Strassburg, Bd. v.
^ Maly, loc. cit.



293.



3 Ihid. Bd. V. (2), S. 14.
^ Loc. cit.



GASTRIC JUICE. 349

Gastric Juice.

Human gastric juice mixed with water or food may be obtained
for clinical purposes by the use of a gastric sound or the stomach pump,
but pure gastric juice cannot be obtained in this way, because when the
stomach is empty the secretion of gastric juice stops, and can only
be initiated by the drinking of water or the taking of food.^

Notwithstanding the considerable number of cases of gastric fistula
in man already enumerated, the details as to the quantitative chemical
composition and physical characteristics of that fluid are very meagre.
Only one set of complete analyses of the fluid has been carried out by
Schmidt, and these, along with certain incomplete analyses by other
observers of the total solids and amount of acid, are all the quantitative
data we possess.

In a case of human gastric fistula, observed by C. Schmidt,^
the fluid obtained was clear as water, less acid than dog's gastric juice,
and had a specific gravity of 1-0022-1 -0024. It scarcely became clouded
on heating, and left on evaporation a brownish-yellow deliquescent acid
residue, which on incinerating left a colourless, neutral, or faintly alkaline
ash, containing no carbonates. On distilling the liquid, only water
came over, until the fluid attained the consistency of oil, then traces of
hydrochloric acid, which became stronger as the process was continued.

In a case observed by Eichet, in which the oesophagus had been
occluded by strong alkali, and the gastric fistula was the result of an
operation, the gastric juice was also colou.iiess, had a faint smell, and
varied greatly in acidity.

Pure gastric juice has also recently been obtained by Fremont ^ from
a fistula in the isolated stomach of the dog. Gastric juice so obtained
is a limpid, clear, colourless, inodorous, very acid, and powerfully peptic
fluid, capable of digesting its own weight of coagulated albumin. The
dog in question weighed 12 kilos., and yielded 800 grms. of gastric
juice daily. If the secretion takes place at the same rate in the human
subject, a man weighing 60 kilos. (132 lbs.) should secrete 4 litres
of gastric juice daily.

Pure gastric juice may be collected from a Pawlow fistula ^ twelve to
fifteen hours after a true meal, by giving the animal a fictitious meal.
The food which is eaten does not reach the stomach, but drops from
an oesophageal fistula. The process of feeding induces reflexly an
abundant secretion of gastric juice, which can be collected in a pure
condition. A dog will go on feeding voraciously in this manner for
hours, and in the course of an hour 200-300 c.c. of gastric juice may be
collected. The animal is said to be unaffected in health by a collection
of an hour per diem.

^ This method is of more service clinically than physiologically as a mode of obtaining
gastric juice in cases of dyspepsia, in order to determine the amount of acidity, and whether
this is due to a normal amount of hydi'ochloric acid or to excess of organic acids, the pro-
duct of bacterial action. See Leube, Sitzungsh. d. phys.-med. Soc. zu Erlangen, 1871.
Heft 3 ; Kiilz, Deutsche Ztschr. f. prakt. Med., Leipzig, 1875, No. 27 ; C. A. Ewald,
" Klinik der Verdaimngskrankheiten," 1890, Bd. i. S. 87; Gamgee, "Physiological
Chemistry," vol. ii. pp. 163-178.

^ The case was that of a healthy woman with a chronic fistula, yielding gastric juice
freely without apparent effect on the health of the patient.

^ Demonstrated by Herzen, International Congress, Bern, 1895.

^Pawlow and Schoumow-Simanowsky, Centralhl. f. Physiol., Leipzig u. Wien, 1889,
Bd. iii. S. 113. See article on "Mechanism of Gastric Secretion."



35°



CHEMISTRY OF THE DIGESTIVE PROCESSES.



Konowaloff^ collected over 10 litres, as above described, and sub-
jected the fluid to chemical examination. It was a clear, colourless,
odourless fluid, which could be kept indefinitely without undergoing
decomposition. When diluted with its own volume of water, it becomes
somewhat cloudy ; with four volumes of water, a permanent opalescence
resulted, which on further dilution eventually disappeared. On neutral-
ising with alkah, a flocky precipitate appeared, redissolving in the slightest
excess. Cooling the juice to 10-11° C. caused a finely granular precipit-
ate to appear, which dissolved again on warming. Its specific gravity
averaged 1-00478; total solids, 0-478 x^er cent.; acidity, equivalent to
0-544 per cent, of hydrochloric acid. When the acid gastric juice is so
removed the reaction of the urine becomes alkaline^ (0-96-1-31 per cent,
of Na^O).

Freshly secreted gastric juice is said to contain traces of proteid,^
which, on standing, is converted into albumoses and peptones ; these, with
traces of mucin, and the two enzymes, pepsin and rennin, are the only
organic constituents.

The inorganic salts consist chiefly of chlorides (with traces of phos-
phates) of sodium, potassium, and calcium, and traces of magnesium
and iron.

The total amount of solids in gastric juice is very small, seldom
amounting to more than 2 per cent., and often being much less. Excess
of alcohol causes a flocky precipitate containing all the organic matter.

Alkalies and alkaline carbonates added to gastric juice cause a
cloudiness or a flocky precipitate of tricalcic phosphate, with traces
of phosphates of iron and magnesium, and some organic matter. The
precipitation of tricalcic phosphate by ammonia shows that calcium is
present as acid phosphate in gastric juice.

Quantitative Composition of Gastric Juice.











I.


II. .


III.


IV.




Human.


Dog.


Dog.


Sheep.


Water




994-40


973-06


971-17


986-14


Total solids










5-60


26-94


28-83


13-86


Organic matter










.3-19


17-13


17-34


4-05


HCl .










0-20?


3-34


2-34


1-23


CaCl, .










0-06


0-26


1-66


0-11


NaCl .










1-46


2-50


3-15


4-37


KCl .










0-55


1-12


1-07


1-52


NH^Cl












0-47


0-54


0-47


Ca3(P0J,) .
Mg3(P0J, .
FePO,








i


0-125 J


1-73

0-23
0-08


2-29
0-32
0-12


1-18
0-57
0-33



The analy.ses are by C. Schmidt, quoted from Maly, Hermann's "Handbuch," Bd. v. (2)
S. 70 ; Ann. d. Chem., Leipzig, 1854, Bd. xcii. S. 42 ; and " Verdauungssafte," S. 44.

Analysis I. is of human gastric juice, obtained from Schmidt's case of
gastric fistula already quoted ; it is evident that this gastric juice contained



^ Inaug. Diss., St. Petersburg, 1893; Jahresh. il. d. Fortsdtr. d. Thier-Chem., Wies-
baden, 1893, Bd. xxiii. S. 289.

^ Schoumow-Sinianowsky, Arch, de sc. hioL, St. Pctersbourg, 1893, vol. ii. p. 462.
^ Hammarsten, " Lehrbuch der physiol. Chem.," Wiesbaden, 1895, Aufl. 3, S. 233.



THE ACID OF THE GASTRIC JUICE. 351

much saliva, as the total solids and amount of acid are much less than those
usually found. Analyses II. and III. are of dog's saliva. Analysis II. gives
the mean of ten determinations, in the case of a dog in which all the salivary
ducts had been ligatured. Analysis III. gives the mean of three, in the case of
a dog with normal salivary glands. Analysis IV. is that of the gastric juice
of a sheep.

The acid of the gastric juice. — The acid of the gastric juice
has probably given rise to more discussion than any other subject in
physiological chemistry. The principal points for consideration are —
(a) the nature of the acid ; (&) the seat of formation and the mode of
origin of the acid ; (c) the function of the acid.

The nature of the acid. — Before discussing this question in detail,
it may be well to state clearly the present state of opinion on the
subject.

It has been demonstrated that hydrochloric acid is the principal acid
of the gastric juice, and that in the purer samples free from food it is
always present, and is almost exclusively the only acid 'present ; while in
gastric juice mixed with food, especially with carbohydrate food, it may
be, and often undoubtedly is, accompanied by lactic acid. C. Schmidt,
from a large number of painstaking and laborious analyses, concluded
that the pure gastric juice of carnivora, obtained after a fast of eighteen
to twenty hours, containB only hydrochloric acid, and no trace of lactic or
acetic acids ; while the gastric juice of herbivora contains, besides hydro-
chloric acid, small quantities of lactic acid, but this is even then probably
from remnants of carbohydrate food.^

Prout,^ in 1824, first showed that gastric juice contains free hydro-
chloric acid by the following method : —

The contents of a stomach were mixed up with water, and, after the
mixture had settled, the clear part was removed by decantation. This
was divided into three eqiial portions, a, h, and c.

(a) The first portion was evaporated to dryness, incinerated, and the
total amount of chlorine in the ash determined by weighing, as silver
chloride.

(h) The second portion was first made alkaline by the addition of
potash, then evaporated to dryness, incinerated, and the total chlorine
determined as before.

(c) In the third portion, the total acidity was determined by titration
against standard alkali, and reckoned as hydrochloric acid.

In portion (a) all the free acid is driven off as well as any which may
be combined with volatile or decomposable bases (such as ammonium
chloride) ; in portion (h) all the chlorine remains, that which was either
free or combined with ammonia becoming converted into non-volatile
potassium chloride ; therefore the difference of (&) and (a) gives the free
hydrochloric acid, plus any volatile chlorides which may be present. In
(c) all the acid is estimated as hydrochloric acid, and by subtracting
this from the difference of (h) and (a) the amount present as volatile
chlorides is obtained.

Prout also showed that when gastric juice is distilled, towards the

^ The stomach of the herbivora retains food for a much longer period than that of
carnivora. Traces of food are usually found in the stomach of the sheep even thirty-six
hours after a meal. See CI. Bernard, " Lecons de physiol. exp^r." 1856, tome ii. p
389.

" Fhil. Trans., Loudon, 1824, part i. p. 45.



352 CHEMISTRY OF THE DIGESTIVE PROCESSES.

end of the process hydrochloric acid passes over. In addition, he tried
to obtain lactic acid from gastric juice, but with negative results.

The remarkable results so obtained by Prout were confirmed by
Children^ in England, by Braconnot^ in France, and by Dunglison
and Emmet,^ with gastric juice obtained from Beaumont's case of
fistula.

When the period at which they were carried out is considered, it
must be admitted that these experiments of Prout were most ingenious,
and he well deserves the honour of being the first to awaken the minds
of men to the conception that the animal organism was capable of
producing such a substance as hydrochloric acid.* Physiological chemists,
however, were chary in believing that the gentler forces of the animal
organism were capable of producing such a substance as hydrochloric
acid, which they were unable to obtain experimentally except by the
use of potent inorganic reagents. Accordingly, objections flowed in
against Prout's work.

Claude Bernard and BarreswiP showed that when sodium chloride
was added to a solution of lactic acid, and the mixture distilled, hydro-
chloric acid appeared in the distillate towards the end of the process
when the mixtm-e was beginning to grow solid. They concluded that the
free acid of the gastric juice was lactic acid. Lehmann ^ ascribed the
free hydrochloric acid of Prout's distillation experiment to the action of
the lactic acid, concentrated by evaporation, on the calcium chloride also
present in gastric juice. Many other observers were also agreed that
the free acid in gastric juice was lactic acid.'' Blondlot ^ about this time
enunciated the hypothesis that the acidity of the gastric juice was due
in part to acid calcium phosphate, and evolved a theory, closely
resembling a much more recent one by Maly, as to the origin of the
acid by the formation of this substance, accompanied by traces of hydro-
chloric and phosphoric acids in the stomach wall, from the sodium
chloride and calcium phosphate of the blood.^ In presence of hydro-
chloric acid it is now known that part of any calcium phosphate present
would be resolved into acid phosphates, but the amount of calcium
phosphate present in gastric juice is altogether insufficient to account for
any appreciable part of its acidity.

While the subject was still in this vexed condition, Bidder and
Schmidt's ^^ classical work on digestion appeared, containing the results
of Schmidt's experiments, to which reference has already been made. As

^ Annals of PMloso'phy , July 1824.

"^ Ann. de cliim., Paris, 1835, tome lix. p. 348.

2 Published with Beaumont's results, 1834.

* As is often the case in great discoveries, Prout seems not to have been much in time
ahead of his fellows. Tiedemann and Gmelin state in the preface to their classical work,
"Die Verdauung nach Versuchen," 1826 (while admitting Prout's priority), that independ-
ently they had found hydrochloric acid in distilling various gastric fluids, and a month
later first saw Prout's publication. However, Prout was clearly ahead of them, both in the



Online LibraryE. A. (Edward Albert) Sharpey-SchäferText-book of physiology; (Volume v.1) → online text (page 49 of 147)