ANIMAL AMIDES. 



CHAPTER IV. 



OF SPERMATIN. 



THIS name has been given to what is considered as the essential 

 part of human semen. When emitted it is a translucent sub- 

 stance, swelled up, and having much the appearance of mucus, 

 only thicker, and frequently in cylindrical concretions. At first 

 it is insoluble in water : but after a certain time it becomes spon- 

 taneously liquid, and then dissolves or mixes readily with water. 

 This remarkable property distinguishes it from all other animal 

 substances. 



When semen, at the instant of its emission, is let fall into alco- 

 hol of the specific gravity 0-833, it becomes opal coloured, it co- 

 agulates into a clot resembling a clue of pack-thread ; as if the 

 spermatin consisted of a long thread which had rolled upon it- 

 self in passing through the canal of the urethra. Thus coagu- 

 lated by alcohol it loses the property of liquefying by standing. 

 When dried it remains thready as before, has a snow white co- 

 lour, and is opaque. In water it gradually softens and assumes 

 the appearance of mucus, especially when boiled in that liquid ; 

 but very little of it dissolves. When the water in which it has 

 been boiled is evaporated to dryness, a white opaque matter re- 

 mains ; one portion of which is soluble in cold, and the remain- 

 der only in boiling water. Both solutions are abundantly pre- 

 cipitated by infusion of nut-galls. The portion of spermatin not 

 dissolved by the boiling water is equally insoluble in a weak so- 

 lution of caustic potash. 



Spermatin coagulated by alcohol is soluble in cold sulphuric 

 acid, to which it gives a yellow colour. Water throws down the 

 portion dissolved white ; and the portion not dissolved contracts 

 when water is added and abandons the acid. The precipitate is 

 insoluble in water, even when assisted by heat. 



Nitric acid while cold gives a yellow colour to spermatin, but 

 does not dissolve it ; when assisted by heat a solution takes place, 

 but the spermatin is again precipitated by the addition of water. 

 In concentrated acetic acid spermatin becomes gelatinous and 

 translucent. When the acid is raised to the boiling tempera- 

 ture solution takes place ; but the liquid still continues muddy, 

 from small undissolved threads remaining interspersed through 



