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the burning of a candle. He also found that carbon dioxide was produced by
putrefaction and by plants during the night-time. Priestley isolated oxygen
and nitrogen, and showed that the change of colour in venous blood on
exposure to the air was due to the action of oxygen, and that blood changed
colour and gave off " phlogiston " even when it Avas separated from the air by
a moist membrane and by the walls of the blood vessels in the lungs. He
concluded that respiration deprived the air of a portion of its oxygen and
imparted to it a quantity of aqueous vapour and "phlogiston."

Lavoisier*^ (1777) extended and explained the discoveries of MayoAv, Black,
and Priestley; he overthrew the old theory of "phlogiston," and pointed out a
distinction between the various so-called phlogistic processes. The calcination
of metals he showed, as Mayow had observed a hundred years before, to be a
combination with oxygen, whereby the metals gained in weight ; in respira-
tion, on the other hand, oxygen was not only absorbed, but combined with
carbon to form carbon dioxide.

Lavoisier and Laplace showed experimentally that animal heat arose from
a process of combustion, oxygen combining, as they thought, Avith carbon in
the blood ; as regards the seat of this combustion, Lavoisier held that it was

1 Phil. Trans., London, 1666, p. 424 ; 1670, pp. 2011, 2035.

" Ibid., 1668, p. 833 ; "Tractatus qiiinque," Oxon. 1674.

^ "Statical Essays," 2nd edition, 1731, vol. i. p. 236 et seq.

■* "Lectures on Chemistry," ed. Robison, Edinburgh, 1803.

^ Phil. Trans., London, 1772, vol. Ixii., p. 147.

^ Hist. Acad. roy. d. sc, Paris, 1775, 1777, 1780, 1789, and 1790.



694



CHEMISTRY OF RESPIRA TION.



in the lungs, but in earlier works he had admitted that it might be in the
other organs of the body.^

It is now known that the essential seat of respiration is in the tissues and
not in the blood. The demonstration of this fact is chiefly due to the work of
Pfliiger and his pupils.

Eespiratory Changes in Aie.

Methods for the measurement of respiratory exchange. — The

simplest and at the same time the earhest method for the measurement
of respiratory exchange, is the analysis of the air of a bell jar, before
and after an animal has been confined in it. Such a method was used
by Black,^ Priestley,^ Lavoisier and Laplace,^ and others.^ The obvious
objection to this method is that the products of respiratory exchange




Fig. 62. — Regnault and Eeiset's respiration apparatus.

accumulate, while the oxygen diminishes, two conditions either of which
disturbs the normal respiratory exchange, and in time causes the death
of the animal.^ Two modifications were introduced by Lavoisier to
remove these defects : in the one, the carbon dioxide was removed as it
accumulated, and a fresh supply of oxygen was added ; in the other, a
constant stream of fresh air was passed through the respiration chamber.
L^pon the first of these principles, Eegnault and Eeisef^ constructed fche
apparatus with which they made numerous and important experiments
upon respiratory exchange. The above figure shows its construction.

1 "QSuvres," 1862, p. 180. - "Lectures on Chemistry," ed. Robison, Edinburgh, 1803.

^ Phil. Trans., London, 1772, vol. Ixii. pp. 147, 168.

^ Hist. Acad. roy. d. sc, Paris, 1780, p. 355. ; "Qiuvres de Lavoisier," tome ii. p. 326.

'^ Berthollet, Journ. f. Chcm. Physik. u. Min., Berlin, 1808, Bd. v. S. 388 ; Legallois,
Journ. f. Chem. u. Phys., Niirnberg, 1817, Bd. xx. S. 113 ; Valentin, "Die Einflusse der
Vagnslahmung auf die Lungen und Hautausdiinstung, " Frankfurt a/M., 1857 ; Arch. f.
exper. Path. u. Pharmakol., Leipzig, 1876, Bd. v. S. 143.

® Bernard, "Lemons snr les effets des substances toxiques," 1857, p. 130; Friedlander
and Herter, Ztschr. f. physiol. Chem., Strassburg, Bd. iii. S. 19 ; Stroganow, Arch. f. d.
ges. Physiol. , Bonn, 1876, Bd. xii. S. 18. See also this article, p. 743.

"^ Ann. dc chim. ctj'hys., Paris, 1849, Ser. 3, tome xxvi.



RESPIRA TOR V CHANGES IN AIR. 695

The carbon dioxide is absorbed from the air by caustic potash, and a
constant supply of oxygen from the reservoirs is driven in, a manometer
in communication with the animal chamber indicating the pressure.
Samples of air for analysis can be drawn from the chamber, and thus
the part played by nitrogen determined, and a control placed upon the
completeness of the supply of oxygen and the removal of carbon
dioxide. Modified forms of Eegnault and Eeiset's apparatus have been
used by Hoppe-Seyler and Stroganow,^ Pflliger and Colasanti,^ Schulz,^
Seegen and Nowak.^

In Scharling's ^ respiration apparatus a constant stream of fresh air
was drawn through the chamber in which the animal was confined. A big
barrel served for the chamber, and air freed from carbon dioxide by
passing through Liebig's potash bulbs was aspirated through the appar-
atus ; on leaving the chamber the air passed through a flask containing
sulphuric acid, which removed the moisture, and through a weighed
potash bulb of huge size, of which the increase in weight gave the
amount of carbon dioxide expired by the animal. As a control, a sample
of air for analysis was removed from the barrel at the beginning and
end of the experiment. In this method the carbon dioxide alone was
determined, and the results were inaccurate, for the absorption was
incomplete, as is shown by the fact that the air leaving the bulbs
rendered lime water turbid. Many other forms of apparatus constructed
upon similar principles have been used.^

With the methods formerly in use it was impossible to maintain a
steady ventilation, and at the same time completely absorb the carbon
dioxide. To overcome this difficulty, Pettenkof er '^ introduced the
following modification. The total amount of air drawn through the
apparatus is measured by a meter ; continuous samples of the air
entering and leaving the chamber are steadily drawn through two
separate systems of absorption tubes and meters for the determination
of the moisture, carbon dioxide, and volume of the samples. The
difference in the amounts of water and carbon dioxide contained in the
two samples, multiplied by the total ventilation, gives the quantity of
moisture and carbon dioxide discharged by the animal. The intake
of oxygen is estimated in the following way. The animal is weighed at
the beginning and at the end of the experiment, and the difference
between the weights of carbon dioxide and water discharged, and the loss
in weight of the animal, represents the oxygen absorbed. Thus if W
represents the initial weight of the animal, and Wi its final weight, then
W - Wi=i^, the loss in weight of the animal. Let CO2 + HgO represent
the weights of carbon dioxide and water discharged during the experi-
ment, then CO2 + H2O — ^^=02, the oxygen absorbed. In thus estimat-
ing the oxygen, it is assumed that, apart from the carbon dioxide and

1 Arcli.f. d. ges. Physiol., Bonn, 1876, Bd. xii. S. 18.

^ Ibid., 1877, Bd. xiv. S. 92.

3 Ibid., Bd. xiv. S. 78.

* Ibid., 1879, Bd. xix. S. 347.

5 Anji. d. Chem. u. Pharm., 1843, Bd. xiv. S. 214.

•^ Allen and Pepys, Phil. Trans., London, 1809, pt. 2, p. 412; Dulong, Ann. de chim.
ct 2^^^ys., Paris, 1841, S^r. 3, tome i. p. 440 ; Despretz, ibid., 1824, tome xxvi. p. 337 ;
Boussingault, ibid., 1844, S^r. 3, tome xi. p. 433 ; Journ. f. 2}raM. Chem., Leipzig, 1845,
Bd. XXXV. S. 402 ; Senator, Arch. f. Anat., Physiol, lo. wissensch. Med., 1872, S. 1 ; Lieber-
meister, Duutsches Arch. f. kliv. Med., Leipzig, 1870, Bd. vii. S. 75.

"^ Sitzungsb. d. k.-bayer. Akad. d. Wissensch. zu Munchen, iiiath.-2)hys. CI., 1862, Bd.
ix. (2), S. 232 ; Ann. d. Chem. u. Pharm., 1862-63, Supp. Bd. ii. S. 17.



696



CHEMISTRY OF RESPIRATION.



water, no weighable amount of nitrogen, or of any other gaseous
substance, is discharged or absorbed by the animal.

The figure below represents the modification of Pettenkofer's
apparatus, which was introduced by Voit for experiments on animals.

The absorption of water is effected by flasks filled with pieces of
pumice saturated with sulphuric acid, and the carbon dioxide is in turn
absorbed by making the air bubble through a long tube filled with a
titrated solution of baryta.^

The advantages of Pettenkofer's method over those previously in use
are these — It is possible, owing to the system of ventilation, to make
experiments upon man ; observations can for a similar reason be much
more prolonged without any danger of disturbance to the normal
respiratory exchange arising from an accumulation of carbon dioxide ;
the absorption of the carbon dioxide is more exact. Notwithstanding
these improvements, Pettenkofer's method possesses several disadvan-
tages and sources of error. The apparatus is complicated and costly, the




Fig. 63. — Voit's respiration apparatus.

determination of the moisture is liable to be inexact, owing to deposition
on the walls of the chamber ; during the process of weighing the animal
there is an intake of oxygen, and an output of carbon dioxide and water,
which are not determined, and can only be calculated approximately ;
the absorption and estimation of carbon dioxide by the titration of the
baryta solution has been shown by Haldane and Pembrey ^ to be less
exact than it was thought to be. The result of these errors falls upon
the estimation of the intake of oxygen, for since 0,2=C02 + HgO — w, it
is evident that the amount of oxygen may be often inexact. This has
been pointed out and proved by C. and E. Voit and Forster.-'*

It has already been mentioned that Voit* has constructed, upon
Pettenkofer's principle, a smaller apparatus for the determination of

1 Baryta was first used by Pettenkofer for tliis purpose, but Dalton liad previously used
titrated lime water.

- Loiulon, Edinburgh, and Dublin Phil. Mag., London, April 1890.

3 Ztschr.f. Biol., Mtinchen, 1875, Bd. xi. S. 126. ^ Ibid., 1878, Bd. xiv. S. 57.



RESPIRATOR Y CHANGES IN AIR.



697



the respiratory exchange in animals. It has the advantages and most
of the disadvantages above mentioned. The human respiration apparatus
in the physiological laboratory, Oxford, has been constructed on the



-C^^




Pumice &
H2SO4



Fig. 64. — Diagram of the human respiration apparatus in the Physiological Laboratory
Oxford. — A. To Aspirator.

principle of Pettenkofer's apparatus, but has been made more exact and
simple by the use of Haldane and Pembrey's method of determining
carbon dioxide and moisture.

A more exact method is that introduced by Haldane.^ It is a




Fig. 65. — Haldane's respiration apparatus. — 1 and 4, soda lime ; 2, 3, and 5, pumice
soaked in sulphuric acid ; Ch, chamber for animal ; M, gasmeter : J, water mano-
meter ; P, aspirator.

modification of the apparatus used by Scharling and Pettenkofer, but
the chief sources of error have been eliminated or greatly diminished,
and the method has been made extremely simple. The construction is
shown in Fig. 65 : —

^ Journ. Physiol., Cambridge and London, 1892, vol. xiii. p. 419.



698



CHEMISTR Y OF RESPIRA TIOJS.



The moistaire is absorbed by pumice saturated with sulphuric acid,
and the carbon dioxide is removed by soda lime, which has been proved
to be such a rapid and excellent absorbent that the total output of
carbon dioxide can be determined directly.^ The animal is weighed in
the closed chamber before and after the experiment, and thus there is
no need to calculate the respiratory exchange during that process, and
no error arises from the deposition of moisture. The air entering the
chamber is freed from carbon dioxide and moisture, and therefore all
the moisture and carbon dioxide in the air leaving the chamber come

from the animal. The
intake of oxygen is
determined indirectly ;
the animal gives off
only carbon dioxide
and water, it absorbs
only oxygen, and the
amount absorbed is
found by subtracting
the loss in weight of the
chamber and animal
from the total loss of
carbon dioxide and
water.

Haldane's method
has also been adopted
for the determina-
tion of the respira-
tory exchange of small
animals and of chick
embryos.^

Another method,
which has been used
for the observation of
the respiratory ex-
change in man, is the
determination of the volume of air respired during a limited period,
and then, from analysis of samples of the inspired and expired air,
estimating the intake of oxygen and the output of carbon dioxide
and water.^ The more recent and exact forms of apparatus con-

^ Haldane and Pembrey, loc. cit.

- Pembrey, Jimrn. Physiol., Cambridge and London, 1894, vol. xv. p. 401 ; 1894-95,
vol. xvii. p. 331.

^ Davy, "Researches," p. 431 ; Ann. d. Phys. u. Clieon., Leipzig, Bd. xix. S. 298 ; Allen
and Pepys, Phil. Trans.. London, 1808, p. 250 ; 1809, p. 404 ; Prout, Ann. Phil., London,
1813, vol. ii. p. 330 ; vol. iv. p. 331 ; Journ. f. Chem. u. Phys., Niirnberg, 1814, Bd. xv. ;
MacGregor, Ann. de chim. eti^hys., Paris, 1841, Ser. 3. tome ii. p. 538 ; Wertbeim, Dcutsches
Arch. f. klin. Med., Leipzig, Bd. xv. ; Wien. med. Wchnschr., 1878 ; Vierordt, "Physiol.
d. Athmens," Karlsruhe, 1845 ; E. Smith, Phil. Trans., London, 1859, vol. cxlix. p. 682 ;
Speck, "Untersuch. ueber SauerstottVerbraucli u. Kohlensiiureausathmung d. Menschen,"
Cassel, 1871 ; Arch. f. ex'per. Path. u. Pharmacol., Leipzig, Bd. ii. S. 405 ; Bd. xii.
S. 1; Lossen, Ztschr. f. Biol., Munchen, 1866, Bd. ii. S. 244; Berg, Deutschcs
Arch. f. Idin. Med., Leipzig, 1869, Bd. vi. S. 291; Leyden, iVid., Bd. vii. S. 536;
Andral and Gavarret, " Recherches sur I'acide carboniqne exhale," Paris, 1843;
Marcet, Phil. Trans., London, 1890, B. ; Proc. Roy. Soc. London, 1891, vol. xlix.
p. 103 ; Jolyet, Bergoni^ and Sigalas, Compt. rend. Acad. d. sc, Paris, 1887, tome cv.
p. 380.




Fig. 66. — Lowy's respiration apparatus.



RESPIRATORY EXCHANGE IN WATER. 699

structed upon these principles are tliose used by Zuntz,^ Geppert^ and
Lowy.^ A diagram of such an apparatus is shown in Fig. 66.

The disadvantage of these methods is that, owing to the attention
of the subject being directed to the breathing, the volume of air
respired during a limited period is not a fair sample upon which to
base an exact calculation, and, moreover, the depth and the rate of
breathing are also liable to another source of disturbance, the resistance
of the apparatus. For these and other reasons,* the results obtained
during short periods of observation are liable to lead to erroneous
conclusions.

Methods similar to those just mentioned have been employed in the
case of animals,^ the mouth and nose being covered with a respiration
mask or the trachea connected by a cannula with the apparatus
necessary for the measurement of the inspired and expired air. It is
obvious that these methods introduce many sources of disturbance ; the
animals, unless horses be used, must be tied down, and in many cases
anresthetised, conditions which markedly affect the respiratory exchange.^
For these reasons the methods of Pettenkofer and Haldane are in most
cases to be preferred, for the animals are placed under conditions as
far as possible normal ; these methods are, however, unsuitable when
operative procedures have to be carried on at the same time as the
determination of the respiratory exchange.

Methods for the measurement of respiratory exchange in water.—

The respiration of fishes was studied by Himiboldt and Provencal '^ in the follow-
ing manner : — The fishes were placed in a flask of water, the gaseous contents
of which had been analysed, and then after an interval a sample of the water
was examined and the alteration in its gases determined. The quantity of
Avater present was measured, and thus it was possible to estimate the amount
of gases absorbed and discharged by the fish. A similar method has been
used by Yernon ^ for the measurement of the respiratory exchange in marine
invertebrates.

Baumert ^ improved this method by passing a stream of water through the
flask containing the animals ; the gases contained in a sample of the water
entering and in the water leaving the flask were determined. A modification
of Eegnault and Keiset's method was introduced by Jolyet and Reynard ; ^^
a stream of air was made to bubble slowly through the water in which the

^ Berl. Min. Wchnschr., 1887, S. 429 ; Arch./. Physiol., Leipzig, 1889, S. 166.

^ Arch. f. exper. Path. u. Pharmakol., Leipzig, 1887, Bd. xxii. S. 368.

3 Arch.f. d. ges. Physiol., Bonn, 1888, Bd. xlii. S. 268 ; ihid., 1888, Bd. xliii. S. 519 ;
ihid., 1891, Bd. xlix. S. 492.

■* See p. 754.

5 Sczelkow, SUzungsh. d. 7c. Akad. d. Wissenscli. Math.-naturiv. CI., Wien, 1862,
Bd. xlv ; Kowalewsky, Ber. d. k. sdchs. Gesellsch. d. TVissensch. 3fath.-2}hys. Kl., 1866,
Bd. xviii. S. Ill ; Sanders-Ezn, ibid., 1867, Bd. xix. S. 58 ; Arh. a. d. physiol. Anst. zu
LeijJzig, 1868, S. 58 ; Scheremetjewski, Per. d. k. sdchs. Gesellsch. d. Wissensch. llath.-
2)hys. KL, 1868, Bd. xx. S. 154; Robrig and Znntz, Aoxh. f. d. ges. Physiol., Bonn,
1871, Bd. iv. S. 57 ; Znntz, ibid., 1876, Bd. xii. S. 522; Tinkler and Oertmann, ibid.,
1877, Bd. xiv. S. 38; Pfliiger, ibid., 1878, Bd. xviii. S. 247; Hanriot and Ricbet,
Compt. rend. Sac. de biol., Paris, 1886 ; Compt. rend. Acad. d. sc, Paris, 1887, tome civ.
p. 435; Fredericq, Pev. scient., Paris, 1880; Piill. Acad. ray. d. sc. de Belg., Bnixelles,
1886.

^ See p. 717. See also '"'Animal Heat," this Text-book, vol. i.

'^ Mem. de la Sac. de phys. et de chivi. d'Arcueil, Paris, 1807, tome ii. p. 359 ; Journ.
f. Chem. u. Phys., Nlirnberg, Bd. i. S. 86.

^ Journ. Physiol., Cambridge and London, 1895-96, vol. xix. p. 18.

'^ "Chem. Untersueh. u. d. Respir. d. Schlammpeitzgers, " Breslan, 1855, S. 24.

^^ Arch, de physiol. norm, etpath., Paris, 1877, tome iv. p. 44.



700 CHEMISTR Y OF RESPIRA TION.

animal was placed ; this air was analysed for carbon dioxide, and the oxygen
absorbed by the animal was replaced by a corresponding amount supplied from
a gasometer.

The consumption of oxygen by animals living in water can be determined
by titrating a sample of the water before and after the confinement of the
animal in a known volume of water. Quinquand^ used for this purpose
sodium hyposulphite, according to Schiitzenberger's method.

The conditions -which affect the respiratory exchange. — A de-
termination of the respiratory exchange not only gives the absolute
value of the oxygen absorbed, and of the carbon dioxide and v^ater ex-
creted, but also shows the relationship between the intake of oxygen
and the output of carbon dioxide. This ratio between the volume of
oxygen absorbed and the volume of carbon dioxide discharged is known as

the respiratory quotient -^5 and indicates how much of the oxygen com-

2
bines with carbon to form carbon dioxide, for one volume of oxygen m

combining with carbon yields one volume of carbon dioxide. Various

conditions influence both the amount of the respiratory exchange and

the relative proportions of the gases, but it must be remembered that

determmations of short duration may give rise to erroneous conclusions,

for oxygen may be stored up for some time within the body, and

carbon dioxide may still be formed and discharged when there is no

intake of oxygen.

The question here arises, Does nitrogen play any active part in
respiration, is there any absorption or discharge of nitrogen ? ^ The
older observers found that nitrogen was sometimes absorbed by the
lungs, and in nearly all of Eegnault and Eeiset's ^ determinations of the
respiratory exchange in different animals there is an alteration in the
amount of nitrogen present in the air, denoting generally a discharge of
a small quantity of nitrogen from the animal. Marchand * had also ob-
tained similar results ; he found in ten experunents upon guinea-pigs
that the average discharge of nitrogen was equal to 0*94 per cent, of the
output of carbon dioxide, and m three experiments on pigeons to 0"85
per cent. Seegen and Nowak^ also found a discharge of nitrogen,
varying from 4 to 9 mgrms. per kilo, and hoar in thirty-two experiments
upon rabbits, dogs, and hens.

This discharge of nitrogen in many cases appears to be due to an
error of experiment.^ Analyses, purposely made by Colasanti '^ to test
this point, showed no discharge or absorption of nitrogen by guinea-pigs.
The small amount observed by other experimenters may be due either
to nitrogen discharged from the alimentary canal or to experimental
errors. According to Jolyet, Bergonie, and Sigalas,^ an amount of
nitrogen varying from yf^ to y^nnj of the oxygen absorbed is taken
up by the l^lood in its passage through tlie lungs of a man or a dog.
In any case the amount of nitrogen absorbed or discharged under

^ Compt. rend. Acad. d. sc, Paris, 1873, tome Ixxvi. p. 1]41.
^ For further details, see Voit, Hennami's "Handbuch," Bd. vi., Th. 1, S. 37.
^ Ann. de chim. ctphys, Paris, 1849, S^r. 3, tome xxvi.
^ Journ. f. prakt. Cham., Leipzig, 1848, Bd. xliv. S. 1.

^ Sitzungsb. d. k. Akad. d. Wissensch. Math.-naturw. CI., Wien, 1875, Bd. Ixxi. (3),
S. 329 ; Arch. f. d. ges. Physiol.. Bonn, 1879, Bd. xix. S. 347.

6 Pettenkofer and Voit, Ztschr. f. Biol., Miinchen, 1880, Bd. xvi. S. 508.
''Arch./, d. ges. Physiol., Bonn, 1877, Bd. xiv. S. 92.
® Compt. reiul. Acad. d. sc, Paris, 1887, tome cv. p. 675.



EXCHANGE OF COLD-BLOODED ANLMALS.



70X



ordiiiary conditions is so small that it may be neglected. It is to
be noted, however, that Colasanti and Tinkler ^ always found small
quantities of marsh gas and hydrogen in the respiration chamber
in which well-fed guinea-pigs were placed ; these gases probably
came from the alimentary canal, for they were not found in the case
of guinea-pigs deprived of food. Zuntz ^ and Tacke found that three-
quarters of the hydrogen and marsh gas formed in the alimentary
canal of a rabbit were absorbed by the blood and discharged by the
lungs.

The respiratory exchange of cold - blooded animals. — When
compared with warm-blooded animals, the respiratory exchange of
most cold-blooded animals is very small, a fact which explains the
small production of heat observed in this class of animals.^ Some
of the earliest determinations were those made by Vauquelin,*
Spallanzani,^ Newport,^ Treviranus,'^ Edwards,^ and Muller.^ They
showed that the quantity of oxygen consumed and of carbon dioxide
produced was for equal weights of animals generally much less in cold-
blooded than in warm - blooded animals, the most marked exception
being in insects. Later researches have confirmed these general conclu-
sions, and have shown the conditions , which chiefly affect the respiratory
exchange in these animals. Of these conditions the most important is
the external temperature, a rise in temperature causing an increase, a
fall in temperature a decrease in the respiratory exchange. In the
following table the results of various observers are expressed for
1 kilo, weight of animal and 1 hour, in order that they may be
comparable : —







1-
s


<v B




























,-v


Wo


■SWo




S






Animal.


•30


CO a
J" C F

>?5 _


Oil
g 0^


00.,
0,




Remarks.


Observer.




^.B


03-S


6 '3




1






Protozoa—
















Collozovmi inerme.






•1113


1-06


16°


One determination.


Vernon. 10


C(ELENTERATA—
















Carviarina lias-






•0087


1-10?


16°


The determinations




tata












- CO., ,
of -— ^ show va-
riations from '36


















Cestui veneris






•0037


•79?


16°


to 2-16.
C0„
— ~ vanes from

t»2 -07 to 2-06.


"



^Arch.f. d. ges. Physiol., Bonn, 1877, Bd. xv. S. 603.
" Arch. f. Physiol., Leipzig, 1894, S. 354. See aLso this article, p. 729.
^Article "Animal Heat," this Text-book, vol. i. p. 792.
"^ Ann. de. chim., Paris, 1792, tome xii. p. 273.

^"Mem. sur la respiration," par Senebier, 1803, p. 184; Journ. f. Chem. Physik
u. Mill., Berlin, Bd. iii. S. 378.

^ Phil. Trans., London, 1837, pt. ii. p. 253.
''Ztschr. f. Physiol., 1832, Bd. iv. S. 23.

* " De I'influence des agens physiques sur la vie," Paris, 1824.
^ " Elements of Physiology," trans. Baly, 1838, vol. i. p. 310.
''■" Jomii. Physiol., Cambridge and London, 1895-96, vol. xix. p. 18.



702



CHEMISTR V OF RESPIRA TION.



TABLE — continued.







o


-§1












,^


ffi-i-


•p-i^




IM








jj M


Ct! 2


.O-C m




5






Animal.


•SO






O


3
p.


Eemarks.


Observer.




^•o


Pi


OS




1






Vermes i—







Online LibraryE. A. (Edward Albert) Sharpey-SchäferText-book of physiology; (Volume v.1) → online text (page 98 of 147)