[Globulin or Crystallin.—This substance was kindly prepared for me from
the lens of the eye by Dr. Moore, and consisted of hard, colourless,
transparent fragments. It is said* that globulin ought to “swell up in
water and dissolve, for the most part forming a gummy liquid;” but this
did not occur with the above fragments, though kept in water for four
days. Particles, some moistened with water, others with weak
hydrochloric acid, others soaked in water for one or two days, were
placed on nineteen leaves. Most of these leaves, especially those with
the long soaked particles, became strongly inflected in a few hours.
The greater number re-expanded after three or four days; but three of
the leaves remained inflected during one, two, or three additional
days. Hence some exciting matter must have been absorbed; but the
fragments, though perhaps softened in a greater degree than those kept
for the same time in water, retained all their angles as sharp as ever.
As globulin is an albuminous substance, I was astonished at this
result; and my object being to compare the action of the secretion with
that of gastric juice, I asked Dr. Burdon Sanderson to try some of the
globulin used by me. He reports that “it was subjected to a liquid
containing 0.2 per cent. of hydrochloric acid, and about 1 per cent. of
glycerine extract of the stomach of a dog. It was then ascertained that
this liquid was capable of digesting 1.31 of its weight of unboiled
fibrin in 1 hr.; whereas, during the hour, only 0.141 of the above
globulin was dissolved. In both cases an excess of the substance to be
digested was subjected to the liquid.”** We thus see that within the
same time less than one-ninth by weight of globulin than of fibrin was
dissolved; and bearing in mind that pepsin with acids of the acetic
series has only about one-third of the digestive power of pepsin with
hydrochloric acid, it is not surprising that the fragments of
* Watts’ ‘Dictionary of Chemistry,’ vol. ii. page 874.
** I may add that Dr. Sanderson prepared some fresh globulin by
Schmidt’s method, and of this 0.865 was dissolved within the same time,
namely, one hour; so that it was far more soluble than that which I
used, though less soluble than fibrin, of which, as we have seen, 1.31
was dissolved. I wish that I had tried on Drosera globulin prepared by
this method. [page 121]
globulin were not corroded or rounded by the secretion of Drosera,
though some soluble matter was certainly extracted from them and
absorbed by the glands.
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