Self -Fertilization Induced by Artificial Means. 159 



same side, and others with sperm from the opposite side. Here 

 also all the eggs segmented. It is perfectly evident, therefore, 

 that the question of self-fertilization in Molgula is not connected 

 with the double condition of the ovo-testis. 



EXPERIMENTS WITH OTHER FORMS. 



In order to find out how generally ether, alcohol, and ammonia 

 excite to greater activity the movements of cilia, of flagella, and 

 of the spermatozoa of other animals, I made a few experiments 

 on certain protozoa and on the spermatozoa of the frog and of 

 the rat. 



Ether, 5 per cent, stops the movements of paramoecium, and 

 kills stentor; 3 per cent, slows up the movements of the former, 

 and causes stentor to throw off its outer layer; the movements of 

 free swimming v^orticellae seemed to be increased; 2 and i per 

 cent, hasten the movements of paramoecium and of stentor. 



Alcohol of 6 and of 8 per cent, slow down the movements of 

 paramoecium and stylonychia, and cause stentor to disintegrate; 

 10 per cent, kills; 4 per cent, appears to be near the limit, and 

 seems to increase their activity; 2 per cent, clearly increases their 

 activity. 



Ammonia 1/200 per cent, kills paramoecium, stentor, and sty- 

 lonychia; and even 1/2000 also kills; 1/5000 per cent, seems to 

 make these protozoa somewhat more active, but I have not suf- 

 ficiently tested this solution. 



Some of the same solutions were used with euglena, which 

 moves by means of an anteriorly directed flagellum. Ether 5 

 per cent, makes them somewhat more active; 3 per cent, less so, 

 and 2 per cent, gives no very noticeable effect. Alcohol 10 per 

 cent, kills; 8, 6, and 4 per cent, make them swim more actively; 

 2 and I per cent, give no definite result. Ammonia 1/200 kills; 

 1/2000 per cent, does not appear to make euglena more active, 

 but other strengths should be tried. 



A male spotted frog [Rana halecina) was killed in No- 

 vember; its testes opened, and the immobile sperm squeezed 

 out into normal salt-solution. It was found that it took 

 some minutes to get a noticeable effect. Ether 5 and 2 



