STUDIES OF FERTILIZATION 529 



1. N/2500 KOH. Produces very rapid agglutination of the 

 spermatozoa; free sperm between show some movement. 



2. N/5000 KOH. No agglutination; no aggregation; sperms 

 fairly motile. 



3. N/7500 KOH. No agglutination; no aggregation; sperms 

 more active. 



4. N/12500 KOH. No agglutination; no aggregation; sperms 

 very active. 



5. N/25000 KOH. No agglutination; aggregations form slow- 

 ly; but sperms are extremely active. 



6. Normal sea-water. Control. Aggregations form in half 

 minute. Very active sperm (maximum). 



This experiment was carried out with the sperm of one male at 

 one time, the solutions being prepared in advance. The limits 

 of the agglutination effect are given. But it is improbable that 

 the inhibiting effect extended to the lower limit, although aggre- 

 gations were formed so slowly in N/25000. The reason for this, 

 as will be shown later, is that the aggregation effect is due to posi- 

 tive chemotaxis to a weak acid, probably CO 2, produced by the 

 spermatozoa themselves. This is neutralized by the KOH so 

 that in spite of the great activity noted in N/25000 KOH aggre- 

 gation cannot take place until after neutralization of the alkali. 



If the behavior of the spermatozoa be observed under the micro- 

 scope at the moment they are put into N/2500 KOH, there is 

 seen momentary great activity of the spermatozoa followed 

 quickly by agglutination as described. 



The relations to NaOH were essentially the same. There was 

 slight agglutination in N/5000 NaOH, and the slightest appear- 

 ance of aggregations in N/25000 NaOH. 



c. To alcohol and ether the sensitiveness is as follows: 



Alcohol : 



(1) 5 per cent, sperm are paralyzed 



(2) 2 per cent, some activity; no aggregations 



(3) 1 per cent, more active, some aggregations may form in five minutes 



(4) 0.5 per cent, few aggregations in about three minutes 



(5) 0.2 per cent aggregations in forty-five seconds 



(6) 0.1 per cent, aggregations in thirty-two seconds 



(7) Control, sea-water; aggregations in thirtj^ seconds 



