BLOOD. 109 



brighter, but, after the lapse of from fifteen minutes to an 

 hour, it became darker than it previously was. It then became 

 of a reddish brown colour, and, after from eight to sixteen 

 hours, it was converted into a pulpy brownish-black matter. 

 The blood of a cat which had taken a drachm of this salt, and 

 had afterwards been killed with cyanogen, exhibited no peculiar 

 appearance. 



Hiinefeld, and some other microscopists, assert that acetic 

 acid dissolves the whole of the corpuscle, with the exception of 

 the nucleus. Miiller, on the contrary, maintains that in 

 frog's blood the colouring envelope is not wholly dissolved, 

 but may still be frequently observed in a pale fine line surround- 

 ing the nucleus. 



The following are my own observations with respect to this 

 test. If a sufiicient quantity of acetic acid be added to freshly 

 drawn blood, so as to give it a decidedly acid reaction, and if the 

 vessel in which it is contained be submitted to a temperature 

 of about 88*^ for half an hour, the blood becomes changed 

 into a thick tar-like mass of a blackish brown colour. 



If water be now added, and the mixture carefully stirred 

 until it is reduced to a magma of an equal consistence through- 

 out, we find that, on examining a portion of this mixture under 

 the microscope, the addition of some more water does not dis- 

 solve the corpuscles ; in fact, they are no longer soluble in 

 water, in consequence of the insoluble compound that has 

 been formed by the acetic acid, and the (casein-like) globulin. 

 If a great excess of water be added, the corpuscles sink; the 

 albumen, and a great portion of the hsematin, which enter into 

 their composition, are dissolved, and they become almost per- 

 fectly clear. They may even be boiled in water, without any 

 change in their form being produced. 



When boiled in acetic acid (unless it be very dilute), they 

 become perfectly dissolved, with the exception of their nuclei.^ 

 According to Miiller and Schultz, a solution of caustic am- 

 monia dissolves the corpuscles more rapidly than a similar 

 solution of caustic potash. The same observers state that 

 alcohol does not dissolve them, but merely produces a shght 

 contraction or puckering, and that the granules of albumen 



' F. Simon's Beitrage zur Kenntniss desBlutes, in Brandes's Archiv, vol. 18, p. 35. 



