220 LILY H. HUIE. 



increase, iudependently of the state of the cytophism. With 

 egg-albumin we do not get these great changes in the nuclear 

 organs till the cell plasm is thoroughly exhausted, while in the 

 case of 10 per cent, amphopeptone we get them while the cell 

 cavity is full of cytoplasm. 



In all cases the process of recuperation begins in the nucleus. 

 The nuclear plasm first becomes abundant, and restoration of 

 the cytoplasm begins in contact with the nucleus, and spreads 

 thence to the remoter parts of the cell. 



3. To answer the question, whether the rapidity with which 

 changes occur depends on the ease with which substances are 

 absorbed, we must deal only with such changes as are charac- 

 teristic of foods. Changes that are produced also by mere 

 contact with insoluble substances must not be taken account of. 



Changes which are produced in five seconds are rapid, yet in 

 this short space of time we get quite specific alterations for 

 two foods so different in their diffusibility as egg-albumin and 

 peptone. But then only the plasm is affected, that is that cell 

 constituent which I have just shown to be most rapidly altered 

 by external stimuli. Nuclear changes, e. g. the increase of 

 chromatin, must depend for their rapidity on the constitution 

 of the food, i. e. on the series of chemical changes the latter 

 must undergo before it is converted into basophile chromatin. 

 In the two cases just cited the length of time required to 

 produce this change differs widely, being about twenty hours 

 in the case of egg-albumin, while one hour suffices for peptone ; 

 and yet from the changes wrought in the cytoplasm in five 

 seconds we might argue that both foods entered the cells with 

 equal rapidity. We may conclude, then, that the rate of 

 plasmic changes depends on the rate of absorption, but that 

 the rapidity of nuclear changes is commensurate only with the 

 digestibility of the food. 



4. In determining the relation between cytological changes 

 in the gland cells on the one hand, and the degree of irritability 

 in the leaves calculated from their rate of closure on the other 

 hand, cytoplasmic changes only constitute our legitimate 

 criterion; for I have shown above that the cytoplasm is the 



