112 DROSERA ROTUNDIFOLIA. Chap. VI. 



prove that gelatiae is far from acting energetically 

 on Drosera. 



In the last chapter it was sho^\-n that a solution of 

 isinglass of commerce, as thick as milk or cream, 

 induces strong inflection. I therefore wished to com- 

 pare 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 

 -^ of a grain, or '135 mg. The four with the isin- 

 glass were much more strongly inflected than the 

 other four. I conclude therefore that isinglass con- 

 tains some, though perhaps very little, soluble albu- 

 minous 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 show- 

 in «• how much moTO 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 experi- 

 ment 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 view of the indirect part \vliich 

 in the 'Medical Record,' January gelatine plays in nutrition. 

 1873, p. 30, an- account of Voit'a 



