98 IIIKOKURO HOXDA. 



As in the case of neutral red, methylene blue entered through 

 the mouth, and in no case penetrated through the cuticle. To 

 stain the entire body of Rhabditis a strong solution was used 

 for the same reason which has been stated in the case of neutral 

 red. After staining 24 hours, some worms were still alive, but 

 others were dead. The anterior part of the living worms as far 

 as the second bull) was deeply stained, hut the remaining part 

 was lighter in colour. 



Such stained worms were placed in 83 per cent, alcohol. The 

 disappearance of the color began at the anterior end. The 

 worms soon died in the alcohol, and the latter then entered 

 through the anus. As far as the second bulb of the esophagus or 

 a little beyond it, the disappearance of the color was due to the 

 alcohol which entered through the mouth; in the remaining 

 regions to that which entered through the anus. A small region 

 of the anterior part of the intestine still remained stained after 

 one hour in alcohol. In one worm I observed that the posterior 

 division of the hermaphrodite reproductive organs was still 

 stained, while the posterior region of the intestine which is found 

 beside them was already reduced in color. 



As in the case of neutral red, in some worms whose posterior 

 ends had been cut off, the stain and alcohol entered through the 

 mouth and the cut end. 



SUMMARY. 



1. Anguillula aceti is highly resistant to acetic acid. To see 

 what is the case in other free-living nematodes Rhabditis elegans 

 was used, and it was found that Rhabditis is much more resistant 

 not only to various kinds of acids, but to other toxic substances 

 also, as compared with the tadpole, Daphnia, Aelosoma and 

 Parameciiini. 



2. When animals were stained in neutral red and in methylene 

 blue, no case in which the stain entered through the cuticle was 

 observed. 



3. The entrance of XaOH and alcohol through the cuticle 

 also could not be observed. 



4. The stains, NaOH and alcohol entered through the mouth, 

 and when the anus and vulva were opened, entered through them 

 as well. 



