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

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K"aCl . . . 0-435 ; PO^. . . 0-916

Ca,(P04)2 . . 0-205

Mg;(P04)2 . . 0-113

Pe2(P04), . . 0-106

Na . . . 0-068

K . . . traces.

Proteids of lyus. — Boedecker^ asserted that pus occasionally contains
gelatin and chondrin in addition to proteids, and a crystalhne acid he
termed chlorrhodinic acid, but Miescher was unable to confirm these
results ; Miescher was also unable to find any myosin, a substance pre-
viously supposed to exist in the cell protoplasm.

My own observations coincide with those of Miescher on this pomt,
and also show that the most abundant proteid is nucleo-proteid. In
fact, the proteids obtained from pus are practically the same as those from
the thymus and other lymphoid structures.

Fibrm ferment was prepared from pus by Eauschenbach.* Consider-
able quantities of proteoses and peptone are generally found in pus, and
are doubtless produced during the retrogressive metamorphosis of the
corpuscles. The original statement that j)us contams peptone was made
by Eichwald ^ and Ilofmeister.*^ Though the method they employed
was not perfectly trustworthy, S. Martin'' showed that they were right
in their conclusions. He placed pus under alcohol for many weeks,

1 Schiifer, "Course of Practical Histology," London, 1876, p. 39.

2 Hoppe-Seyler's " Med. Chem. Untersuch.," 1871, Heft 4, S. 497.
^ Ztsclir. f. rat. Med., Leipzig, N.F., Bd. vi.

* Inaug. Diss., Dorpat, 188-3 ; Jahresh. ii. d. Fortschr. d. Thier-C'lwm., V^'^ieshaden Bd.
xiii. S. 134.

° Verhandl. d. 2)hys-med. Gesellscli. zto Wurzburg, 1864, S. 335.
^ Ztschr.f. physiol. Chem., Strassburg, 1864, Bd. ii. S. 295.
'^ £rit. Med. Jo^mi.. London, 1890, voL ii. p. 234.


and then dried it and extracted it with water. Proteoses and peptone
went into solution, the other proteids ha\dng been coagulated. It is pro-
bable that some of the symptoms which accompany the suppm^ative pro-
cess is produced by the entrance of these substances into the cux'idation.^

There is httle to add concerning the other constituents of pus cells.
The large increase of fat, lecithin, and cholesterin confirms the fact of
fatty degeneration, evident to the microscope ; free fatty acids may even
be found in old pus, forming crystalline deposits.

Glycogen can often be demonstrated in pus corpuscles micro -
chemically by the use of iodine ; ^ Salomon ^ separated it from the cells
in appreciable quantities.

Pigments (pyocyanin, pyoxanthose) are frequently foimd m pus, and
are produced by chromogenic bacteria (Fordos, Liicke, Fitz, Kunz,

The proteids of red marroiu cells. — In the lymphatic glands and
thymus the cells are non-eosinophile ; in the red marrow the cells are
mostly eosinophile. Sherrington ° showed that the eosinophile granules
give microchemically the reaction for phosphorus, introduced by Lihenf eld
and Monti ; ^ the cells themselves were investigated macrochemically by
J. E. Forrest.'^ The marrow used was obtained from the interior of
rabbits' femora and horses' ribs.

His results were very like those obtained from other cellular
structm^es. Two proteids only were obtainable in any quantity, these
were a cell globulin, coagulating at 47°-50^, and a nucleo-proteid. The
latter contams a high percentage of phosphorus,^ namely, 1'6. Haemo-
globin is present in small quantities, and proteose and peptone are absent.

Epithelium. — Our knowledge of the tissues included imder the
heading epithelium is principally histological. There is no reason to
suppose that the proteid constituents of the protoplasm and nucleus are
in any way different from that found in cells generally.

Mucin is formed in many situations, both in the cells of mucous
glands and in goblet cells. It is also the principal constituent of the
cementing material between the cells.

Mucus is the name given to the secretion which owes its sKminess to
mucin. Mucus also contains epithehal cells, more or less disintegrated, and a
few leucocytes. It has an alkaline reaction, and contains a certain small pro-
portion of proteids, extractives, and salts, similar to those of the blood. In
some cases, the mucinoid material in secretions is really a nucleo-proteid.
Thus, in the bile of some animals like the ox, there is very little true mucin,
hut the viscidity is almost entirely due to nucleo-proteid ; ^ in human bile, on
the other hand, the viscid material is mucin, very little nucleo-proteid being

^ Ott and Collmar, Journ. Physiol., Camhridge and London, vol. viii. p. 218 ; Ki'ehl
and Matthes, Dcutsches Ardt. f. ktin. MccL, Leipzig, 1896, Bd. liv. S. 501 ; Arch. f. exper.
Path. u. Pharmakol., Leipzig, 1896, Bd. xxxvi. S. 437.
^ Ranvier, Progres vied., Paris, 1877, p. 422.
" Deutsche, med. Wchnsehr., Leipzig, 1877, No. 35.

* Compt. rend. Acad. d. sc, Paris, 1860, tome li. p. 215 ; Arch. f. klin. Chir.,
Berlin, 1862, Bd. iii. S. 125 ; Quart. Journ. Mic.r. Sc, London, Jan. 1880, p. 106 ;
Monatsh. d. Chem., Wien, Bd. ix. S. 361 ; Compt. rend. Sac. dc hiol., Paris, 1889,
p. 438.

'^ Proc. Roy. Soc. London, 1894, Bd. Iv. p. 161.

" Ztschr. f. physiol. Chem., Strasslnirg. 1893, Bd. xvii. S. 410.

■^ Journ. Physiol., Cambridge and London, 1894, vol. xvii. p. 174.

^ Halliburton, ibid., 1895, vol. xviii. p. 307.

'•• Paijkull, ZtscJir. f. physiol. Chem., Strassburg, Bd. xii. S. 196.


present.'^ The mucus of urine has also been stated to be nucleo-proteid in
nature.'^ K. A. H. Morner^ investigated healthy human urine ; each experiment
necessitated the use of 80-90 litres. He found proteid or proteid-like materials
partly in suspension in the ordinary mucous cloud or nubecula, and partly in
solution. From tlie nubecula he separated a specific member of the mucin
group, which he calls urine mucoid. This probably originates from the mucous
membrane of the urinary passages. It contains C 49*4, N 12"74, and
S 2'3 per cent. ; and in its general properties agrees with ovo-mucoid pretty
closely (see p. 63). The soluble proteid in urine, which is present in the
merest traces, is chiefly serum albumin, but some is precipitable by acetic
acid, and this part consists of a nucleo-proteid ; precipitated with it was
found a small quantity of chondroitin sulphuric acid (see "Cartilage").

The mucin of the respiratory passages has been investigated by F. Miiller.*
He finds it is true mucin, not nucleo-proteid. It yields from 25 to 32 per cent,
of reducing substance. This is a nitrogenous derivative of a hexose, and is
probably glucosamine.

Keratin and the slxeleMns are epithelial products which have already been
described (p. 72). The enamel of teeth, although epithelial in origin, will
be taken with the skeletal tissues. The epithelium of secreting glands will
be studied with those glands and their secretions.

Glandulak Oegans.

The liver. — The fresh hver is alkahne in reaction, but after death
soon becomes acid from the development of sarcolactic acid.

The nmnber of organic substances in the liver is very nmnerous.
There are proteids and nnclein from the hepatic cells ; there are
substances like glycogen, sugar, and fat, stored up within the cells, or
produced from stored-up substances. Gelatin and mucin are obtainable
from the connective tissue framev^ork. There are also extractives like
xanthine, hypoxanthine, and uric acid ; lastly, a small proportion of
inorganic constituents.

The proportion of water is about 75 per cent. v. Bibra^ gives the
following numbers : —

Water . . 76 "17 per cent.
Insoluble tissues 9 '44 ,,'
Proteids . .2-40 „

Gelatin . . 3-37 per cent.
Extractives . 2-40 ,,
Fats . .2-50 „

Proteids of the liver cells. — These were first investigated by P. Plosz.*^
He found that, accompanying the onset of acidity after death, the
liver became harder and less transparent; he therefore compared the
condition to the rigor mortis of muscle, and sought for myosin by the
methods Klihne had introduced for separating muscle plasma. He did
not, however, find any myosin. He extracted the proteids by means of
saline solutions of various strengths, and found —

(1) A proteid coagulating at 45° C., wholly soluble in gastric digestion ;
(2) a nucleo-proteid, coagulating at 70° C., yielding an insoluble residue of

^ Hammarsten, Kon. Ges. der Wiss., Upsala, 1893 {Scparat-abzug) ; Baginsky and Somer-
feld, Verhancll. d. physiol. Gesellsch., Bei'lin, 1S94-5, Nos. 13, 14, 15 in Arch. f. Physiol.,
Leipzig, 1895, S. 362.

^ Lonnberg, UjKala Luknrcf. Fork., vol. xxv. ; K. Miirner, Hygiea, Stockliolni, 1892,
vol. lii ; Oberma3'er, Ccntralhl. f. Idin. Med., Bonn, Bd. xii.

3 SJcandin. Arch. f. Physiol, Leipzig, 1895, S. 332.

■* Sitzungsh. d. Gesellsch. z. Bcford. d. ges. Natuno. zu Marhurg, 1896, No. 6.

^ V. Bibra, "Chemische Fragmente neber die Leber," 1849.

^ Arch. f. d. ges. Physiol., Bonn, Bd. vii. S. 371.


nuclein on gastric digestion ; (3) a globulin coagulating at 75° C. ; and
(4) alkali albiunin.

A good many years later/ I repeated these experiments ; and, like
Plosz, failed to find myosin. Myosin appears to be a specific constituent
of muscle, and has not been found anywhere else. The hardening that
occiu's in the liver after death, and which is very shght, is possibly due
to the solidification of the fat in the cells ; though it is also qirite possible,
as Plosz suggests, that if coagulation does occm- iii the cells with the
formation of a myosui-like clot, this takes place so rapidly that our
present methods do not enable us to separate its precursor from the cells.

The proteids I obtained by the use of saline solutions were fom- in
number : —

1. A globulin (cell-giobidin) coagulating at 45°-50° C.

2. A nucleo-proteid which coagulates at about 60° C, and is identical
with that obtainable by Wooldridge's acetic acid method from the cells.
It contains 1"45 per cent, of phosphorus. It does not become viscous on
admixture with neutral salts, and the sodimn chloride method of
preparing nucleo-proteids is not appUcable to it. It produces intra-
vascular coagulation.

3. A globuhn coagidating at 70° C.

4. An albumin in mere traces, wliich coagulates at about the same

Other organic constituents of the liver cells. — Urea, m-ic acid (especially
in birds), xanthine, and hypoxanthine, are found in the hver ; - leucine
and tyrosine are found in cases of acute yellow atrophy, and in
phosphorus poisoning.^ Various other substances have been described
as occasional constituents.^

A substance called jecorin, containing phosphorus (CiosHisgN^SPaO^-),
was separated from the liver by Drechsel.° In its properties it some-
what resembles lecithin ; it, however, reduces Fehhng's solution, which
lecithin does not. According to Baldi,*^ it occm^s in many other organs-
spleen, muscle, brain, etc.

The question of the iron-containing nucleins of the hver (Zaleski's
hepatin, Schmiedeberg's ferratin,'^ etc.) is alluded to on p. 69. The
iron in the hver is increased in diseases, like pernicious anaemia, wliich
lead to increased destruction of red blood corpuscles ; it is normally
greater in young (especially new-born) aiumals than m older ones.
Animals appear to enter the world with a store of ii'on in the liver, and
to a less degree in the spleen, wMch lasts them until they are able to
take foods other than milk, which is poor in iron.^

^ Journ. Fliysiol., Cambridge aud London, 1892, vol. xiii. p. 806.

- Scherer, Ann. d. Chcm., Leipzig, Bd. cvii. S. 314 ; Cloetta, ihid., Bd. xcvii. S. 2SP.

^ Sotaitsclicwsky, Ztschr. f. i^hysiol. Chcm., Strassburg, Bd. iii. S. .391; see also
Riilimanii, Bcrl. Idin. Wchnschr., 1888, S. 43 aud 44.

•* Guanine, inosite, scyllite (Frericbs and Stadeler, Mitth. d. Ziirich. natur. Gcscllsch.
1858) ; cystine (Hoppe-Seyler, " Physiol. Cliem.," S. 718) ; sarcolactic acid, probably formed
after death.

^ Journ. f. prald. Chcm., Leipzig, Bd. .xxxiii. S. 435.

^ Arch./. Physiol., Leipzig, 1887, Snppl., S. 100.

"^ For recent work in ferratin and iron in the liver, and absorption of iron compounds
as food, see F. Yav, Ztachr. f. 2yhi/siol. Chcm., Strassburg. Bd. xx. S. 377 : "Woltering,
ibid., Bd. xxi. S. "186 ; Hall, Arch. f. Physiol., Leipzig, 1896, S. 49, 142; Cloetta,
Arch. f. exper. Path. u. Pharmakol., Leii)zig, 1896, Bd. xxxiii. S. 6; Hochhaus and
Quincke, ihid., S. 152; Quincke, ibid., S. 182.

^ Meyer and Pernon, Ztschr. f. Biol, Mlinchen, Bd. xxvii. S. 439; Lapicquc, Compt.
rend. ^oc. de, bioL, Paris, tome xli. p. 435.









Iron oxide



Inorganic constituents of the, liver. — Oidtniaiin^ found I'l per cent, of
inorganic material in the liver, of which potassium phosphate, as in
many other organs, is the most abundant. His numbers per cent, are : —

Phosphoric acid . 43-37
Sulphuric acid . 0-9

Silicic acid , . 0-27

Chlorine . . 2-5

Manganese, lead, copper traces.

F. Kriiger and Lenz '- found that the liver cells of the calf contain about
70 per cent, more calcium than in the ox. During the foetal period there are
two maxima and two minima in the amount of calcium, which varies inversely
with that of iron. In the liver cells of adult men, Kriiger and his assistants ^
found 2-38 of sulphur, 1-28 of phosphorus, and 0-77 of iron per cent. In new-
born children the three numbers are respectively 5-56, 1*54, and 0-314.

The spleen. — The percentage of water in the adult human
spleen varies from 69-4 to 77-5, the solids, from 31-6 to 22-5, of which
30-1 to 21-6 consist of organic, and from 1-1 to 0-9 of inorganic, matters.*

During life the spleen is alkaline. Acidity sets in after death, due
to the formation of sarcolactic acid.^

The organic constituents of the spleen are proteids and hsemoglobin,
xanthine,*^ hypoxanthine, uric acid,'' glycogen,^ inosite,^ scyllite,^*' cerebrin,^^
cholesterin, lecithin, and jecorin.^''^ Various fatty acids (formic, acetic,
butyric) described by Scherer " are, no doubt, derived during the process
of distillation from the proteids. Leucine and tyrosine, which are
absent from the fresh organ, are often found as a result of putrefactive
changes (Hoppe-Seyler). The inorganic constituents are very like those
found in the liver, except that sodium are more abundant than
potassium salts.^"^

The proteids of the spleen. — Gourlay ^^ found that the proteids which
can be extracted from fresh spleen resemble those found in lymphoid
structures ; the most important of these are a cell globulin coagulating
at 49°-50° C, and a nucleo-proteid coagulating at 57-60° C. Bottazzi^^
confirms these observations in the main. The nucleo-proteid can be pre-
pared either by Wooldridge's or the sodium chloride method, and, like that
obtained from other cellular organs, produces intravascular coagulation.

^ "Die anorg. Bestandtheile dei' Leber," Linnich, 1858.

' Ztsclvr.f. Biol, Mlinchen, 1895, Bd. xxxi. S. 392. ^ Ihid., S. 400.

* Oidtniann, loc. cit.

5 Hirschler, Ztschr. f. physiol. Chem., Strassburg, Bd. xi. S. 41.

*"' Scherer, Ann. d. Chem., Leipzig, Bd. cvii. S. 314 ; Stiideler, ibid., Bd. cxvi. S. 102 ;
Neubauer, Ztschr. f. anal. Chem., Wiesbaden, Bd. vi. S. 33 ; Gorup-Besanez, Ann. d.
Chem., Leipzig, Bd. xcviii. S. 1 ; Cloetta, ibid., Bd. xcix. S. 289.

■^ Sclierer, Gorup-Besanez, Cloetta.

^Hoppe-Seyler, "Med. Chem. Untersnch.," Bd. iv. S. 495; Abeles, CentralU. f. d.
tiled. Wissenselb., Berlin, 1876, No. 5.

** Cloetta, Scherer.

1° Frerichs and Stadeler, Mitth. d. Zurich, natur. Gesellsch., 1855.

" Hoppe-Seyler. 12 galdi. Arch. f. Physiol., Leipzig, Suppl., 1887, S. 100.

^^ Verhandl. d. phys.-med. Gesellsch. zu Wilrzburg, Bd. ii. S. 323.

"Oidtniann gives the following percentages: — Soda, 35-45; phosphoric acid, 18-30;
sulphuric acid, 1-5-2*5; potash, 9-17; oxide of iron, 7-16; silica, 0-2-0-7; lime, 7;
clilorine, 0-5-1 -3 ; manganese, copper, lead, traces. For a comparison of the percentage of
sulphur and phosphorus in the hepatic and splenic cells at different ages, see F. Kriiger,
Ztschr. f. Biol., Miinchen, 1895, Bd. xxxi. S. 400.

^^ Journ. Physiol., Cambridge and London, 1894, vol. xvi. p. 23,

^^ Ann. di chim. e difarm., 1895, vol. xxi.


Another point in connection with the spleen relates to the question
whether or not proteoses or peptones are obtainable from it ; this is im-
portant, because Sidney Martin ^ has found that the proteoses of diseases
(diphtheria, tetanus, etc.) accumulate in the spleen, v. Jaksch ^ states
that normal spleen contains " peptone " ; but the careful work of Gourlay,
in which he used Devoto's ammonium sulphate method and the alcohol
method failed to detect any.

Lymphatic glands. — The capsule yields gelatin and mucin like
connective tissue structures generally. The reticular tissue yields
reticulin (see p. 72) and gelatin (see p. 70). The chemistry of the cells
has been already described (p. 81).

In a lymphatic gland, about two-thirds are water, the remainder
solids. The tissue is alkaHne during life, and turns acid, due to the
development of sarcolactic acid, after death.^

Thymus. — This is also principally lymphoid tissue, and the above
remarks apply equally well to it. ISTothing special is known of the
chemistry of the concentric corpuscles. The presence of extractives
like xanthine and hypoxanthine has been noted by Scherer, Gorup-
Besanez, Trerichs, Stadeler, etc., whose writings have been already
referred to. Schindler "^ has estimated the " nuclein or alloxuric bases "
(see p. 67) obtainable from the thymus of the calf, with the following
results : —

Percentage in Adenine.




Fresh tissue
Dry tissue





The high percentage of adenine is noteworthy. Like the other
organs already described, the reaction, alkaline during life, becomes
rapidly acid after death. The acid is sarcolactic acid.^

The thyroid. — This organ is also alkaline during life, but becomes
acid after death ; this is due to sarcolactic acid (Moscatelli).

Various extractives (fatty acids, xanthine, hypoxanthine, etc.) have
been found in it by Gorup-Besanez, Scherer, Frerichs, and Stadeler.
Inosite has been found by Frankell^ and by Tambach.'^ The main
constituents of the thyroid, however, are proteids, and a proteid-like
substance from the colloid material in the acini.

Oidtmann found in the adult thyroid, 82-24 water, 17'66 organic and
Ol inorganic material per cent. In an infant's thyroid the numbers
were 77-21, 22-35, and 0-44 respectively.

The importance of the chemistry of the thyroid arises from the fact that
the administration of thyroid extracts has been attended with curative
results in cases where the thyroid is absent, or no longer forms the
internal secretion wdiich is believed to be necessary for the nutrition of
the nervous system.

^ Goulstonian Lectures, Brit. Med. Jov.rn., London, March 1892.

- Ztschr. f. physiol. Chem., Strassburg, 1892, Bd. xvi. S. 243.

" Hirschler, Ibid., Bd. xi. S. 41.

■* Ibid., Bd. xiii. S. 438.

5 Moscatelli, ibid.. Bd. xii. S. 416.

^ JVicn. med. III., 1895, No. 48 ; 1896, Nos, 13, 14, 15.

^ Pharm. Centr.-BL, Leipzig, 1896, Bd. iv. S. 119.


Various attempts have been made to discover the active principle in
the thyroid which is responsible for its curative properties. Notldn^
attributes the activity of the gland to its proteid constituents, especially
to the one called tliyreoinotdd by Bubnow,^ which acts after the
manner of an enzyme.

Gourlay ^ made a thorough investigation of the proteids obtainable
from the organ. His conclusions were as follows : —

1. The only proteid that can be obtained in any quantity from the
thyroid is a nucleo-proteid.''^ This may be prepared 1:)y either the acetic
acid or sodium chloride method, and when intravascularly injected
causes thrombosis.

2. This is derived, at any rate partly, from the colloid matter in the
acini; it yields no sugar on treatment with dilute mineral acid, and
is therefore not a mucin or mucoid. Moreover, the microchemical
method of Lilienfeld and Monti shows that it contains phosphorus.
The absence of mucin is confirmed by Frankel and by Hutchison.

3. Small quantities of albumin are also obtainable.

A year later Frankel ^ separated from the gland a crystalline
material, with the formula CyHjiN^Oj, which he called thyreo-antitoxin,
though the experimental and clinical evidence quoted hardly seem to
justify the name.

Koos and Baumann ^ have discovered an iodine-containing material,
which occurs chiefly in combination with the proteid of the organ, but
partly free. It is remarkable in being insoluble in 10 per cent, hydro-
chloric acid, a reagent which dissolves all the other substances present.
It was previously known that the active substance was very stable.
Thyroid feeding is followed by as good results as injection of thyroid
extracts ; the active substance therefore resists the action of digestive
ferments. The substance was named by its discoverers !!%ro-'z'o(i'iw, or
iodo-thyrin; it contains 9'3 per cent, of iodine, and 0-56 per cent, of phos-
phorus. It is not probably a derivation of nuclein, but its constitution is
not yet known. The amount of iodine per gramme of the organ in human
adults varies from O'S to 0'9.

Whether this substance is really the important proximate principle in
thyroid extracts and by inference in the normal internal secretion of the
organ, must still be left to the future. For, though Eoos and Baumann
state that it acts in every way like thyroid extracts, Gottlieb '^ has been
unable to confirm the statement, though possibly, as Auerbach ^ suggests,
this is to be attributed to his having used preparations very poor in iodine.
Weak points in the theory appear to be the absence of the substance
in the thyroids of children, and in some animals like dogs unless they
are put on a particular diet (dog biscuits). Small quantities of iodine
are found also in the thymus.

^ Wien. vied. TVchnschr., 1895, Nos. 19 and 20; Virchoivs Archiv, 1896, Bd. cxliv.
S. 224. The ferment theory was also urged by White and Davies, Brit. Med. Journ., London,
1892, vol. ii. p. 966.

^ Ztsclir.f. physiol. Chem., Strassbnrg, Bd. viii. S. 1.

^ Journ. Physiol., Cambridge and London, 1894, vol. xvi. jd. 23.

■* Morkotun [Vracli, St. Petersburg, 1895, No. 37) gives the composition of this
nucleo- proteid as— 0, 51-46 ; JST, 15-56 ; P, 0-32 ; H, 6-94 ; S, 1-5 ; 0, 24-22 per cent.

5 Wien. vied. BL, 1895, No. 48 ; 1896, Nos. 13, 14, and 15.

'^ Ztsehr. f. flnj&iol. Clievi., Strassbnrg, Bd. xxi. S. 19, 319, 481 ; xxii. S..l,18.

'^Deutsche med. TVchnschr., Leipzig, Bd. xxii. S. 235,

^ Centralbl. f. Physiol., Leipzig, 1896, Bd. x. S. 133. For various other references
to clinical work on this question, see ibid.. No. 6. For the influence of iodo-tliyrin on
metabolism, see P. Voit, Ztschr.f. Biol , Miinchen, 1897, Bd. xxxv. S. 116.


This discovery of a compound containing iodine in the animal body
is a very remarkable one, but is not unique. Almost simidtaneously with
Baumann's announcement, Drechsel ^ pubhshed a research on the horny
skeleton of Gorgonia cavolinii. Here he found iodine in organic com-
bination, and on decomposition the skeleton yielded a crystalline amido-
acid (iodo-gorgonic acid) of uncertain constitution, and with the formula
CiHgNIO.2. Drechsel has also found iodine in the hair of a syphihtic
patient, taking iodide of potassium. With reference to the thyroid, he
suggests the very reasonable hypothesis that this organ produces more
than one active substance, and that the different substances have
different actions. He has confirmed the existence both of Baumann's
iodo-thyrin and of Frankel's thyreo-antitoxin, and has fm'ther separ-
ated out a second crystalline base. Hutchison,^ however, finds that
the proteid-free extracts which contain these bases are physiologically
inactive. He finds that the activity is coiniected with the iodine-con-
taining colloid substance. He distinguishes between the colloid of the
acini and the nucleo-proteid of the epithelium lining them. The former
is the active constituent, and is by gastric digestion decomposed into
two parts. One part is proteid ; it contains a Httle iodine, and has
feeble physiological powers. The other part is not proteid, and not
nuclein. It is more active, and contains the greater part of the iodine

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