Eoss Granville Harrison 



213 



of the embryos. The basis of comparison of the two specimens is rendered 

 all the more exact by the fact that the sections of both were run through 

 the staining fluids simultaneously. 

 Experiment 6. Palustris embryo, 

 five days. — There is a marked in- " ''< 



crease in the vacuoles in the axial . 



sarcoplasm of the muscle fibers, .' 



while in the control specimen, 



reared in water, there is but very ' - ! )'.i • 



slight vacuolization. 



Experimeiit 6. Palustris evibryo, 

 seven days. — In. this specimen the 

 yolk is practically gone. The vac- 

 uolization of the fibers of the myo- 

 tomes is marked. The fibers are 

 separated from each other by clear 

 spaces. The jaw muscles show some 

 vacuolization, but in a much less 

 marked degree than in the myo- 

 tomes. The striated fibrillar sub- 

 stance is also well marked in the 

 former. 



Experiment 7. Larvae of six 

 days. — Two specimens, one of 

 which had been kept in a 0.025 per 

 cent solution, and one control 

 reared in water were imbedded side 

 by side and cut and mounted to- 

 gether. The contrast in the mus- 

 cular tissue in the two specimens is 

 not marked. TJiere is more vacuo- 

 lization in the drugged larva, Fig. 

 IS, but this characteristic is much 

 less marked than in the specimen 

 just described. This condition is 

 due in all probability to the cir- 

 cumstance that the solution of the 

 acetone-chloroform was slightly 

 weaker than in the former case, 

 and also to the fact that, owing to 

 the high temperature, the larva 



Fig. 16. Fig. 17. 



Fig. 16. Two muscle fibers from the ninth 

 mj-otome of a norma) palustris embryo, three 



had attained its development in six ^laj-s older than the stage used in the experi- 



■,„ „ ment. 



days of exposure to the drug, in- r^a. 17. Two muscle fibers from the myo- 



stead of in seven, as in the former tome of a palustris embrj'o kept for three days 



,• ^ in a 0.03 per cent solution of acetone-chloro- 



iiibiaiice. form, y, yolk spherule. 



The most striking- feature of the experiment described in full above is 

 the extraordinary rapidity of the recovery from the action of the acetone- 

 chloroform; in several other similar experiments the recovery was even 

 more rapid. Thus, in one instance (experiment 1), a virescens embryo. 



