G. F. Barker—Physiological Chemistry. —‘ 61 
animals were chemically homologous with the embryonic tis- 
sues of the higher ones).” Its quantity as compared with that 
in the caterpillar and maggot excludes the hypothesis of im- 
mature chitin. Nor in the tenia, certainly, can it have a mus- 
cular future, raeeee it might be there provided for the use of 
the ova, The small amount in the generative apparatus at 
first opposes: thiei view, but the analogy between the ascaris, 
with its glycogen, and the plant, with its blanched starch- 
storing tissues, is striking. May not “migration” occur as 
well in the animal as in the vegetable economy : 
(73.) Jarr& has published the results of some examinations 
of the. organs of persons variously diseased, for glycogen.* 
Only in rare cases was he able to find this substance in the 
organs of diabetic ponees, and then only traces were detect- 
ed. Once he found it in the brain, once in the spleen, and 
once in the pia mater ; in the latter case the patient had died 
from suppurative meningitis 
74.) A paper was sent to the French Academy on the 19th 
of March, 1866,, by Bizio, in —- after alluding to the 
discovery of amyloid matter by Brrnarp in the liver and the 
foetal tissues, he notices particularly McDonnell’s research, 
and states that the large amount of this substance found by 
—50 per cent of the dried foetal pulmonary tissue—led 
him to undertake the examination of this question. In reflect- 
ing upon the conditions of animal life at the period when this 
glycogen is so abundant in the tissues, aided also by other 
considerations, he concluded that this substance was the more 
abundant the less the energy with which the force of innerva- 
tion acted, a view which the facts have subsequently confirmed. 
Proceeding from this hypothesis, he argued that the glycogen 
should be as abundant in the classes of adult inferior animals 
as in the embryonal tissues of superior ones. Certain acepha- 
lous mollusks were first examined for glycogen ; as, for exam- 
ple, the oyster (Ostrea edulis L.), the Ca rdium edule 4. 
the Mytilus edulis L., the Solen siliqua L., and the Pecten 
jacobeus L. They all contained it, some of them in large 
proportion. To nthe it, the finely-divided mollusk is boiled 
for a long time in water, the water poured off, and the onera- 
tion repeated twice or thrice. The liquids thus obtained are 
concentrated, precipitated by alcohol, and the precipitate 
treated with strong acetic acid. Only a portion dissolves ; 
the supernatant liquid is decanted, and the residue is washed 
with acetic acid. The acid solution i is precipitated again with 
alcohol, and the precipitate is again dissolved in acetic acid ; 
* Virchow’s Archiv., xxxii., 20; Jahresb., 1866, 753. +0. R., lxii. 675. 
