SEMEN. 501 



becomes black, and gives out a strong odour of ammonia. If the 

 residue be lixiviated with water, an alkaline solution is obtained, 

 which gives crystals of carbonate of soda, and doubtless of com- 

 mon salt. A little phosphate of lime remains. 



The constituents of semen, according to the analysis of Vau- 

 quelin, are, 



Water, . 90 



Spermatin, . 6 



Phosphate of lime, 3 



Soda, . . ] 



100 



But this analysis was made before chemistry had acquired the 

 requisite precision. It cannot, therefore, be depended on. In 

 a previous chapter of this volume, while treating of spermatin, 

 the more recent experiments of Berzelius on human semen have 

 been stated. 



II. Fourcroy and Vauquelin published a set of experiments on 

 the milt of the carp in the year 1807,* from which it appears 

 that the nature and composition of this substance is different .from 

 that of every other hitherto examined. The milt of this fish, as 

 is well known, has a whitish colour, a soft consistence, a greasy 

 feel, and a smell similar to that of fish. It is neither acid nor 

 alkaline. When triturated with potash, no ammoniacal odour is 

 exhaled, and it forms with the alkali a thick magma. Thirty 

 parts of milt mixed with six parts of potash, and a sufficient 

 quantity of water, and distilled, yielded only traces of ammonia, 

 coming obviously from some muriate of ammonia, which exists 

 naturally in the milt. When milt is dried slowly in a moderate 

 heat, it loses three-fourths of its weight, becomes yellow and 

 brittle. When heated in a platinum crucible it softens and then 

 melts, exhaling yellow vapours having the smell of animal oil. 

 The charcoal formed contains a notable quantity of uncombined 

 phosphoric acid, together with some phosphate of lime and phos- 

 phate of magnesia. As the acid did not exist in the milt, it must 

 have been formed during the combustion ; and hence it follows, 

 that milt contains a notable quantity of phosphorus as a consti- 

 tuent. 



One hundred and twenty-three parts of fresh milt, cautiously 



* Ann. de Chim. Ixiv. 5. 



