SPERM 93 



suits. However, F. R. Lillie (1913b, 19 19 p. 102) stated that in Arbacia 

 punctulata, the sperm are attracted to CO 2 and to egg water which 

 contains "fertihzin". But Loeb (1914c) thought that LiUie's explan- 

 ation of his experiments was incorrect, and that they did not neces- 

 sarily show chemotaxis. Later, Loeb took a decided stand against 

 chemotaxis of eggs and sperm and expressed his views in two of his 

 books, The Organism as a Whole (1916, p. 92) and Forced Movements^ 

 Tropisms and Animal Conduct (1918, p. 139). The subject has been taken 

 up again recently by Rothschild (1951a, b, 1952), who has come to 

 the conclusion that "in the animal kingdom spermatozoa probably 

 meet or coUide with eggs by chance" (1952, p. i), and that "chemo- 

 taxis of spermatozoa toward eggs has never been observed with cer- 

 tainty" (1951b, p. 40). For the older work see Morgan's Experimental 

 Embryology, Chapter II, 1927. 



See Part IV, Polyspermy. 



h. Polyspermy 



i. Physiology 



For references to the physiology of the sperm o^ Arbacia punctulata, such 

 as respiration, enzymes, etc., see under the appropriate topic in Part IV 

 which treats of both eggs and sperm. 



j. Seminal fluid 



The seminal fluid of Arbacia punctulata has been especially studied by 

 Hayashi (1945, 1946) with the following results. Sperm are as motile 

 in seminal fluid as in sea water; they retain their fertilizing power 

 longer. The pH of the seminal fluid is 7.6-7.9; its osmotic pressure is 

 10% lower than sea water; it contains less than 10 \xg reducing sugar 

 in 5 cc. ; it contains 2.5 mg. protein per cc. ; it does not act as a nutrient 

 for the sperm. It does not contain anti-fertilizin, but increases agglu- 

 tination. It delays the fall in respiration following the increase after 

 dilution. 



The seminal fluid or "seminal plasma" o^ Echinus esculentus has been 

 studied by Rothschild (1948b) with special regard to Og tension; he 

 also noted the large amount of potassium in the seminal fluid. 



k. Techniques 



Method of keeping sperm 



Remove the testes from a freshly opened animal as intact as possible, and place 

 them, undiluted, in a small covered stender dish (about 3 cm. diameter). Place 



