BLOOD. If) 9 



Let us now proceed with the metamorphosis of the blood- 

 corpuscles ; the next question for consideration is this : Jt^hat 

 changes do the hcematin and globulin undergo ? It has been 

 ah'cady shown that both these substances must undergo an 

 entire change diu'ing the period of development of the blood- 

 corpuscles, that terminates in their consumption or solution. 

 The plasma contains a peculiar colouring matter, hacmaphgein, 

 to which it owes its yellowish colour/ and which cannot accu- 

 mulate in it beyond a certain amount, because it is con- 

 tinuously removed by the kidneys ; it is, in fact, this consti- 

 tuent that gives the yellow or yellowish-brown tint to the 

 urine. 



It can hardly be doubted that the hsemaphaein is a product 

 of the metamorphosis of the hsematin ; especially, if it can be 

 proved that it is formed solely from the blood-corpuscles, and 

 that it is contained in them to a large amount. We can 

 obtain from the serum only slight traces of hsemaphsein, but 

 the clot yields a considerable amount of colouring matter, 

 which must be therefore contained in the blood-corpuscles. 

 The luemaphsein is formed from the hsematin during the de- 

 velopment of the blood-corpuscles, and the change is probably 

 accompanied by an absorption of oxygen and a separation of 

 carbon; the youngest blood-corpuscles must consequently con- 

 tain less hsemaphsein than those that are older; and when the 

 act of development terminates in theu- solution, they no longer 

 possess any hfematin, but only hsemaphsein. In a normal 

 state, the consumption and production of the blood-corpuscles 

 must be nearly balanced, and consequently the proportion of 

 the hsematin to the hsemaphasin will remain tolerably constant ; 

 when the metamorphosis of the blood is accelerated (i. e. when 

 the circulation is quickened, and the mutual action between 

 the blood and oxygen is increased) more blood-corpuscles will 

 be consumed in a given time than in the normal state, and 

 the consumption will especially include the older ones which 

 abound in colouring matter, and which in their development 

 are approximating to the stage of solution. 



' When the serum, after the separation of the clot, is of a reddish tint, which is 

 not unfrequently the case, blood-corpuscles are suspended in it. In icterus the serum 

 is often of a brownish red colour, in consequence of the presence of bihphaein ; in 

 this case the colour" rapidly changes into a green, on the addition of nitric acid. 



