Chap. VI. DIGESTION. 113 



two leaves with the smaller cubes only to a moderate 

 degree. ' The jelly on all four was by this time lique- 

 fied, 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, and half-minim drops were 

 given to four leaves ; so that each received about -^-l-^ 

 of a grain (-135 mg.) of the jelly ; and, of course, 

 much less of dry chondrin. This acted most power- 

 fully, for after only 3 hrs. 30 m. all four leaves were 

 strongly inflected. Three of them began to re- 

 expand after 24 hrs., and in 48 hrs. were completely 

 open ; but the fourth had only partially re-expanded. 

 All the liquefied chondrin was by this time absorbed. 

 Hence a solution of chondrin seems to act far more 

 quickly and energetically than pure gelatine or isin- 

 glass; but I am assured by good authorities that it 

 is most difficult, or impossible, to know whether 

 chondrin is pure, and if it contained any albumi- 

 nous compound, this would have produced the above 

 effects. Nevertheless, I have thought these facts worth 

 giving, as there is so much doubt on the nutritious 

 value of gelatine ; and Dr. Lauder Brunton does not 

 know of any experiments with respect to animals on 

 the relative value of gelatine and chondrin. 



31ilk. — We have seen in the last chapter that milk 

 acts most powerfully on the leaves ; but whether this 

 is due to the contained casein or albumen, I know not. 

 Eather large drops of milk excite so much secretion 

 (which is very acid) that it sometimes trickles down 



