2O6 EDWIN' J. COHN. 



effects of "egg water" upon the physiological condition of sper- 

 matozoa. 



When sperm are added to egg water, their activity is tremen- 

 dously increased. If they are then immediately transferred to 

 the ripe eggs of the same species in sea water it is to be supposed 

 that their fertilizing power will for a very short time be at least 

 as great, if not greater than the fertilizing power of less active 

 sperm. The experiments by Fuchs seem to have been conducted 

 in this way. The experiments which are recorded in Table XIV. 

 were carried out in such a way as to make the time during which 

 the sperm were in the "egg water" as short, and the volume of 

 sea water in which the sperm were added to eggs as great, as 

 possible. A few experiments appear to agree with those of 

 Fuchs in that the "egg water" increased the fertilizing power of 

 the sperm. The results are irregular, however, for if the con- 

 centration of the "egg water" is too great, or if the time during 

 which spermatozoa are in the "egg water" is too long, so that 

 the activity of the spermatozoa is decreased, the fertilizing power 

 of spermatozoa is not so great as is that of spermatozoa that have 

 been in sea water. This seems to have been the case in the ex- 

 periment of Lillie quoted by Fuchs; in which "to five watch 

 glasses containing each eight drops of water or of different con- 

 centrations of egg-extract were added three drops of 'opalescent ' 



V 



sperm-suspension. After 12 minutes, a drop of a suspension of 

 fresh eggs was added to each.' 5 per cent, of the eggs in the 

 water segmented, but none of those in the four different concen- 

 trations of extract" (Fuchs, H. M., 1915, p. 275; Lillie, F. R., 

 1913, p. 558). It will be noted that in this experiment of Lillie's 

 insemination took place in the egg extracts. Repeating this 

 procedure as nearly as possible, Fuchs was able to obtain higher 

 percentages of fertilization in his "extracts" than in the sea 

 water. This difference in the effect of egg "extracts" upon the 

 fertilizing power of spermatozoa is probably due to the relative 

 concentration of the "extract" and the sperm, and to the absolute 

 strength of the former. For, as Schiicking early observed, al- 

 though spermatozoa are stimulated by low concentrations they 

 are "lamed" (that is, their activity is temporarily decreased) by 



