DESICCATION IN PHILODINA ROSEOLA. 375 



the absence of the food granules is again noticed. The objection 

 might have been offered in the case of the dried stomach that 

 the failure of the food granules to become apparent was due not 

 to their actual absence but to a chemical change incidental to 

 the drying process which made them entirely lose their affinity 

 for stains. If this were the case it seems that upon the addition 

 of water the granules would again resume their normal staining 

 reaction. That this possibility is not realized in fact is apparent 

 from an examination of the stomach tissue shown in Fig. 15. 

 The nuclei have resumed their normal appearance. The cyto- 

 plasmic syncytium of the stomach tube compares favorably 

 with that in the normal animal, while scattered about through 

 it are vacuoles which probably mark the previous positions of 

 the food particles which have disappeared. In any event, the 

 food particles have been used up and the stomach tissue has the 

 same appearance as is found in cases where the animal is not 

 dried, but starved. 



The trochal cilia in animals recovering from desiccation under 

 the highest magnification cannot be seen to be different from 

 those in the normal or even in the dried animal. Absolutely 

 no change is observable. 



Upon the addition of water the hypodermal layer of the 

 integument rapidly swells and assumes its normal thickness. It 

 might be mentioned here again that if there were any sign of a 

 protecting gelatinous capsule it should be observed at this 

 point when the different tissues swell and draw apart. But 

 here, as before, there is absolutely no sign of such a gelatinous 

 envelope. 



The cells of the peripheral layer of the brain of rotifers re- 

 covering from desiccation show the characteristic chromatic 

 ring in their nuclei (Fig. 29, PI. V.). This, at first sight, is 

 remarkable because the nuclei of similar cells in the dried animals 

 do not particularly show such a disposition of the chromatic 

 material. However, the cells in the peripheral layer of the 

 brain are among the smallest in the rotifer body and their nuclei 

 are correspondingly minute. The small amount of chromatin 

 in each nucleus could migrate toward the nuclear membrane 

 without being especially apparent. But, as was pointed out in 



