OF VITAL PHENOMENA 163 



the sperm contains lecithin and therefore fatty acid, and since 

 fatty acids and many other organic substances cause membrane 

 elevation and segmentation, it should be possible to cause seg- 

 mentation with sperm extract. Robertson (1912) washed sperm 

 in H 2 0, precipitated the extract with BaCl 2 , redissolved it in 

 HC1 and reprecipitated it with acetone. The resulting "oocytin" 

 caused membrane elevation. 



