836 SUMMARY OF CURRENT RESEARCHES RELATING TO 



effect of various chemical reagents of higher temperature, and of mechanical 

 injury on the ova of Strongijlocentrotus lividus, and also the effect of 

 external agents on the sperma. 



(1) Ova before fertilization, (a) Nicotin. A mixture of one drop of 

 concentrated nicotin solution with 100 grms. sea water acting for 3-5 

 minutes, or with 1000 grms. sea water acting for 10-15 minutes. By 

 stronger solutions or by longer immersion the degree of over-fertilization 

 can be increased. By immersion for one hour in a solution of 1 : 100 the 

 ova were not killed, (h) Morphia hydrochlorate solutions of • 1-0 • 2 per 

 cent, must act for one hour. Solutions of • 4-0 • 6 per cent, produced after 

 1/2-1/4 hour a few cases of polyspermia, (c) Strychnine. Solutions of 

 ' 005 per cent, produced a notable influence in 10 minutes, a remarkable 

 one in 20 minutes. Solutions of • 1 per cent, in 5 minutes effected strong 

 polyspermia ; in solutions of 0-25 the ova died in 25-60 minutes. 

 {d) Chloral hydrate. A 0*2 per cent, solution produced polyspermia in 

 4 J hours, while a • 5 per cent, solution did so in 5 minutes, but after 

 4 hours the ova did not seem susceptible of fertilization, (e) Chloroform 

 (the eggs placed in watch-glasses filled with sea water were exposed to the 

 vapour of chloroform under bell-jars). The ova died in 15-20 minutes, a 

 shorter time produced polyspermia. Chloroform water (chloroform shaken 

 up with sea-water) prevented fertilization, the membrane immediately 

 separating from the ovum. (/) Cocain. Solutions of 0*025 and 0-05 per 

 cent, produced polyspermia in 5 minutes. A longer action weakened the 

 ova too much, [g) Chinium sulfuricum. A solution of • 005 per cent, 

 produced perfect polyspermia in 75 minutes ; in a shorter time the action 

 was correspondingly less. A solution of 0-05 per cent, produced in 10 

 minutes and still more so in 15 minutes, very considerable polyspermia. 



(2) Sperma before fertilization, (a) Nicotin. In solutions ten times 

 as strong as used for ova the spermatozoa were mobile and quite fertile 

 after two hours. (&) Chloral hydrate. In • 5 per cent, solution motion 

 ceased in 5 minutes, but returned on addition of fresh sea water even after 

 35 minutes' action of the solution, and were fertile, (c) Chinin. A 0*05 

 per cent, solution produced diminution after 5 minutes, and in 35 minutes 

 cessation of movement. When the water was changed the motion only 

 returned slowly and with imperfect fertilization of ova. {d) Strychnine. 

 A • 05 per cent, solution had a retarding influence after acting for 3 hours, 

 (e) Morphia, A 0*5 per cent, solution seemed to have no influence. 

 Fertilization was normal after 3/4 hour. 



(3) Influence of chemical agents on the course of fertilization. Chinin 

 and chloral diminished the radiation ajipearances in the protoplasm con- 

 siderably, and hence inhibited the progress of the internal fertilization 

 appearances, (a) The authors immersed the fertilized eggs for 10 minutes 

 in a • 5 per cent, chloral solution. (1) 1 minute. (2) 1^ minute. (3) 5 

 minutes. (4) 15 minutes, after fertilization, and then examined a part of 

 the fresh or fixed material. Specimens from each of these four divisions 

 were taken at iuterviils from 10 minutes to 5 hours after the action of the 

 chloral. The general results did not quite coincide with the previous 

 observations, one part being more, the rest less strongly affected by the 

 reagents, while the changes in the nucleus and protoj)lasm were not impeded 

 to a like extent. 



(4) Effect of chemical reagents after fertilization, (a) Nicotin solution 

 1-100) after acting for 3/4 hour on fertilized eggs, no appreciable result. 

 6) 0"1 per cent, solution of nicotin acting for 10-60 minutes had only 



slight influence, (c) Morphia. A ■ 1 and • 6 solution had only a retarding 

 action; and a 05 solution and a 0-4 actincr for 30-GO minutes had a 



