Spermine, Choline, Ergothioneine 169 



method of Roman (1930) is based on the same principle but involves 

 an analysis of iodine instead of nitrogen 



HOCH2CH2N+ 



CH3I CH3 

 CH3 



Choline 



Compared with other animal tissues and body fluids, semen ranks 

 as one of the richest sources of choline. It owes its high choline 

 content to the seminal plasma and not to spermatozoa as such. 

 In rat, Fletcher, Best and Solandt (1935) found the following dis- 

 tribution of total choline (mg./lOO g.): seminal fluid 514, brain 325, 

 liver 260, pancreas 232, stomach 152, uterus 74, fat 23, blood 22. 

 The composition is similar in other species, including man, where 

 values exceeding 2000 mg./lOO ml. semen have been observed. This 

 may explain a statement by Marcille (1931) that a positive Florence 

 reaction can be obtained with dried human semen even when it is 

 diluted with 1000 parts of water. However, there is no general 

 agreement about the sensitivity of Florence's reaction. In fact, many 

 investigators have criticized the reaction, mainly because the same 

 specimen of semen will occasionally give a negative reaction at first, 

 and a positive result later. This peculiar behaviour of human semen 

 was elucidated by Kahane and Levy (1936, 1937) who discovered 

 that human semen examined immediately after ejaculation contains 

 practically no free choline, but that choline accumulates in semen 

 gradually on standing, as illustrated by the following experiment: 

 from 3-5 ml. semen mixed with 20 ml. water, consecutive 2 ml. 

 samples were withdrawn and deproteinized by boiling with 9 ml. 

 ethanol for 2 minutes; the quantitatively collected filtrates were 

 evaporated, the residues extracted with dry ether and redissolved in 

 water; choline was precipitated from the aqueous extracts with the 

 Reinecke reagent and determined bromometrically. Results, which 



Table 23. Choline in human semen (Kahane and Levy, 1937) 



Time after 



ejaculation 2 min. 10 min. 1 hr. 6 hr. 22 hr. 48 hr. 120 hr. 

 Choline liberated 



(mg. per 100 



ml. semen) 70 860 1600 2120 2030 2500 530 



