434 EFFECTS OF REAGENTS [SECT. 1 97. 



to redness. — The following results were obtained by an examina- 

 tion of the spermatic filaments of the bull. Concentrated sulphuric 

 acid gives a yellowish colour to the semen, but in twenty-four 

 hours is found not to have dissolved the spermatozoa. With 

 grape-sugar and sulphuric acid, the semen becomes a purplish-red, 

 but the colour only affects the substance between the filaments. 

 Strong nitric acid colours the semen yellow, the filaments to some 

 degree, as well as the amorphous portion, but beyond a slight 

 shrivelling, the spermatozoa undergo no other change from this 

 re-agent in twenty-four hours. Even when boiled for two minutes 

 with nitric acid, the filaments are not dissolved. Hydrochloric 

 acid in the cold produces no alteration in them : boiled with this 

 acid, the spermatozoa remain recognizable, but they become re- 

 markably pale, and their tails appear shrivelled. Boiled with 

 Millon's reagent (nitrate of mercury) the semen assumes a more or 

 less deep shade of red, and the filaments themselves are somewhat 

 coloured. Glacial acetic acid produces no effect either in the cold 

 or after prolonged boiling, and the spermatozoa will keep for 

 weeks in this acid. A much more powerful influence than that 

 of the acids is exerted by the caustic alkalies ; but even these have 

 very little power in the cold, whatever the strength of the solution. 

 At higher temperatures the filaments dissolve, the tails first, and 

 the bodies much more slowly, and it takes a long time to dissolve 

 them altogether, even when the solution contains fifty per cent, of 

 alkali. The conclusion from these reactions is, that the substance 

 of the spermatic filaments of mammalia (on that of other ver- 

 tebrata, see my treatise- before quoted) is not a body of an albu- 

 minous nature, but rather that it has affinities with the substance 

 which composes the wall of cell-nuclei and elastic fibres; it is not, 

 however, so very difficult of solution in caustic alkali as the elastic 

 fibre. 



The movements of the spermatozoa are not often to be seen in 

 the unmixed semen, as it is too concentrated ; they usually occur 

 first in the mixed secretion contained in the vesicuke seminales 

 and in emitted semen, or they are seen when pure semen is diluted. 

 These movements are effected solely by alternate curvings together 

 and extensions of the filiform appendages, constituting a serpen- 

 tine movement. The changes of position thus produced, at any 

 rate in man and in mammalia, are so rapid and diverse, crawling, 

 twisting, and twitching, the head always moving in advance of the 

 tail, that the elements of semen were formerly regarded as ani- 

 malcules. The duration of the movements depends upon various 



