(1) Human semen. Data on dry weight, total nitrogen, and electrolytes 

 (excluding inorganic phosphate): Huggins, Scott and Heinen (1942); COg: 

 Sheldovsky et al. (1940); urea: Goldblatt (1935^); Lactic acid: Lundquist 

 (1949Z>). Remaining data are our own; the results on non-protein nitrogen, 

 fructose, and citric acid content are based on analysis of semen from ten 

 individuals. The ash content of human semen is about 0-9% (Slovtzov, 

 1902, 1916); the ash contains 3% sulphur (Albu, 1908). According to 

 Infantellina (1945) human semen contains 30 mg./lOO ml. glutathione. 

 The values reported for ascorbic acid are 12-8 mg./lOO ml. (Berg, Huggins 

 and Hodges, 1941) and 2-6-3-4 mg./lOO ml. (Nespor, 1939); using Roe's 

 method, we found 10-2 and 12-4 mg./lOO ml. in two specimens. 



(2) Bull semen. Data on electrolytes (except magnesium and inorganic 

 phosphate): Bernstein (1933); COg: Shergin (1935); remaining data are our 

 own, based on analysis of ejaculates from ten bulls (average volume of 

 ejaculate 4-5 ml.; sperm concentration 985,000/jul.). Other constituents of 

 bull semen include (mg./lOO ml.): thiamine 0-028-0-152, riboflavin 0-152- 

 0-306, pantothenic acid 0-230-0-466, and niacin 0-248-0-554 (VanDemark 

 and Sahsbury, 1944). Ehlers et al. (1953) reported the following mean 

 values based on the analysis of 663 samples of semen (mg./lOO ml.): 

 fructose 552 (S.D. 169), citric acid 724 (S.D. 192). For additional data see 

 Rothschild and Barnes (1954). 



(3) Ram semen. With the exception of the CO2 content (Shergin, 1935), 

 the data are our own, based on analysis of material pooled from ten 

 ejaculates (average volume of single ejaculate 1-2 ml.; 2,940,000 sperm/jitl.). 



(4) Boar semen. Data on dry weight, electrolytes and total nitrogen: 

 McKenzie, MUler and Bauguess (1938); remaining data our own. Addi- 

 tional information in Table 7. 



(5) Stallion semen. Data on dry weight, electrolytes, total phosphorus 

 and CO2 content from Slovtzov (1916), Bernstein (1933), Shergin (1935) 

 and Milovanov (1938); remaining data our own. 



(6) Dog semen. Much work has been done on the dog prostatic secretion 

 (see text). Whole semen has been analysed by Slovtzov (1916) and the 

 following composition found (mg./lOO ml.): dry weight 2450, albumin, 

 globulin and nucleoprotein 866, mucoprotein 57, and lipid 182. Electro- 

 lytes have been examined by Bernstein (1933); dog semen is distinguished 

 by a high content of chloride (620-657 mg./lOO ml.). Fructose and citric 

 acid occur only in traces. 



(7) Cock semen. In material from six pooled ejaculates, 5,100,000 

 sperm//il., we found (mg./lOO ml.): 57 total anthrone-reactive carbo- 

 hydrate, of which 4 was fructose and 41 glucose (determined by glucose 

 oxidase); 44 total phosphorus, of which 27 was acid soluble; 2 ammonia. 

 In six individual specimens of cock semen we found from 7-7 to 81 

 mg./lOO ml. glucose but never more than 4 mg./lOO ml. fructose. 



33 



