38 ILLINOIS ACADEMY OF SCIENCE 



2. (Sector 4). If the sperm-receptors are occupied, the 

 spermatozoa cannot fertilize. The Godlewski phenemenon 

 (Antagonism of sperm suspensions.) 



3. (Sector 5). If the egg receptors are occupied, fertiliza- 

 tion cannot take place. Purely Hypothetical. 



4. (Sector 6). If the ovophile side-chain of the fertilizin 

 be occupied, fertilization cannot take place. Inhibiting action 

 of blood. 



5. (Sector 2, b and c). If the spermophile side-chain be 

 occupied, fertilization cannot take place. Action of anti-ferti- 

 lizin; prevention of polyspermy. 



It is obvious that these five blocks are purely chemical in 

 their conception, but the possibility of other blocks in the fer- 

 tilization reaction must not only be conceded, but strongly em- 

 phasized; as the essential reaction takes place across the egg 

 membrane, the condition of this membrane, whether permeable 

 or impermeable, is an essential factor in the reaction. The re- 

 action must also be subject to the usual environmental condi- 

 tions of comparable bio-chemic phenomena, such as tempera- 

 ture, ionic constitution of the medium, etc. Modification of 

 these conditions will determine the occurence or non-occur- 

 rence of the fertilization reaction. 



This theory transfers the fertilizing power from some hy- 

 pothetical substance contained in the spermatozoon to a defi- 

 nite substance contained in the egg itself, in relation to which 

 the sperm acts merely as an activator. It is therefore radically 

 opposed to the theory that the sperm carries a lysin or other 

 substance that acts directly on the cortical layer of the egg. 



The mechanism which we have been considering concerns 

 the cortical changes in the egg. The question therefore arises, 

 whether the second phase of fertilization which I have shown 

 previously to be dependent on the penetration of the sperma- 

 tozoon, is likewise a three-body reaction, and if so whether the 

 fertilizin is the intermediate body in this case also? This is 

 a problem that I have not yet fully worked out, but the indi- 

 cations are for a positive answer to both these questions. 

 There are a number of facts of considerable interest in this 

 connection. (1) As is well known for Arbacia, spermatozoa 

 may penetrate ovocytes but without fertilizing them ; In Chae- 

 topterus I have observed the same fact. (2) If the cortical 

 changes are induced mechanically or chemically in the egg of 

 Nereis, there is a stage where the spermatozoa may still pene- 

 trate but without causing complete fertilization. Miss Allyn 

 demonstrated the same facts for Chaetopterus. (3) Dr. Kite 



