32 ILLINOIS ACADEMY OF SCIENCE 



tion, of self-fertilization, of the antagonistic action of sperm 

 suspensions of different phyla, of the fertilizing effect of 

 injured spermatozoa, etc., are methods that have recently been 

 employed for the direct analysis of fertilization, and which 

 have aided greatly in the definition of problems, though but 

 little in their solution. 



I have therefore attempted for some years to make a direct 

 analysis of the fertilization problem, and have developed two 

 new methods of analysis : ( 1 ) The use of sperm-suspensions as 

 indicators of reactions. (2) The study of fertilization by 

 inhibitors. 



The first method was suggested by the fact that many of 

 the most delicate of biological reactions are determined by the 

 use of living cells as indicators. In the field of immunology no 

 other indicators are known for bodies concerned in such re- 

 actions in many cases. The sperm cells of a specie;, might be 

 expected to serve as indicator of substances formed by the egg 

 with which reaction normally takes place in fertilization. As 

 regards the second method, it is obvious that an analysis of the 

 reaction concerned in fertilization might be attempted by 

 agents which would hinder the normal course of events at 

 any place. This would constitute a method of analysis by 

 which the total reaction might be broken up into its elements. 



I. Results from the Use of the Sperm Suspensions as In- 

 dicators. 



If some of the sea-water from a suspension of eggs of Ar- 

 bacia be added to a milky suspension of the sperm of the same 

 species in sea-water, a very rapid agglutination is obvious to 

 the naked eye, resulting in the formation of detached white 

 masses of agglutinated spermatozoa, leaving the fluid more 

 or less clear, depending on the strength of the reaction, 

 In a few minutes the agglutinated masses break up into their 

 constituent elements and the suspension becomes milky again. 

 The reaction cannot be repeated in the case of the sperm sus- 

 pension, if it is incomplete in the first instance. In chemical 

 terms it cannot be repeated after saturation. The spermatozoa, 

 however, retain their vitality. We have then a combination of 

 some elements of the spermatozoa with a secretion from the 

 ripe ova, which so alters the physical character of the sperm 

 cells that they adhere in masses. The reaction in question is 

 without prejudice to the life of the spermatozoa. 



The agglutinating substance is produced only by ripe eggs 

 of Arbacia, and not by immature eggs or by any other tissue of 

 the species; in other words, only fertilizable eggs produce it. 



