prove that gelatine is far from acting energetically on Drosera.
In the last chapter it was shown that a solution of isinglass of
commerce, as thick as milk or cream, induces strong inflection. I
therefore wished to compare its action with that of pure gelatine.
Solutions of one part of both substances to 218 of water were made; and
half-minim drops (.0296 ml.) were placed on the discs of eight leaves,
so that each received 1/480 of a grain, or .135 mg. The four with the
isinglass were much more strongly inflected than the other four. I
conclude therefore that isinglass contains some, though perhaps very
little, soluble albuminous matter. As soon as these eight leaves
re-expanded, they were given bits of roast meat, and in some hours all
became greatly inflected; again showing how much more meat excites
Drosera than does gelatine or isinglass. This is an interesting fact,
as it is well known that gelatine by itself has little power of
nourishing animals.*
Chondrin. This was sent me by Dr. Moore in a gelatinous state. Some was
slowly dried, and a small chip was placed on a leaf, and a much larger
chip on a second leaf. The first was liquefied in a day; the larger
piece was much swollen and softened, but was not completely liquefied
until the third day. The undried jelly was next tried, and as a control
experiment small cubes were left in water for four days and retained
their angles. Cubes of the same size were placed on two leaves, and
larger cubes on two other leaves. The tentacles and laminae of the
latter were closely inflected after 22 hrs., but those of the
* Dr. Lauder Brunton gives in the Medical Record, January 1873, p.
36, an account of Voit s view of the indirect part which gelatine plays
in nutrition. [page 113]
two leaves with the smaller cubes only to a moderate degree. The jelly
on all four was by this time liquefied, and rendered very acid. The
glands were blackened from the aggregation of their protoplasmic
contents. In 46 hrs. from the time when the jelly was given, the leaves
had almost re-expanded, and completely so after 70 hrs.; and now only a
little slightly adhesive fluid was left unabsorbed on their discs.
One part of chondrin jelly was dissolved in 218 parts of boiling water,
98