THE CORPUSCLES OF THE BLOOD 95 



of acid haematoporphyrin. It can be prepared by treating a drop 

 of defibrinated blood with a small amount of strong sulphuric 

 acid, shaking well, and diluting the resultant mixture with more 

 concentrated acid until the mixture is sufficiently diluted to be viewed 

 through the spectroscope. The spectrum presents two bands: one 

 narrow, just to the red side of the line D; another broader, between 

 D and E. 



The sulphuric acid splits haemoglobin into its constituents 

 haematin and globin ; the haematin is then deprived of its iron with the 

 formation of haematoporphyrin. 



Alkaline haematoporphyrin is produced in a similar manner to 

 the acid, but very strong alkali is used. Alkaline haematin is first 

 formed, but this is subsequently broken down to iron-free alkaline 

 haematin or alkaline haematoporphyrin. The spectrum of this body 

 presents four bands a narrow band between C and D, two between 

 D and E, and a broad band between E and F. 



Haematoporphyrin may occur in the urine after such drugs as 

 sulphonal have been taken, and is usually of the alkaline variety. 

 The formula for haematoporphyrin is C 16 H 18 N 2 3V It is closely related 

 to the pigment bilirubin of the bile, which has the same empirical 

 formula. 



If a solution of a copper salt in ammonia be added to haematopor- 

 phyrin, turacin is formed a pigment found in the red feathers of 

 certain birds (plantain-eaters). The important pigment of plants, 

 chlorophyll, is a near ally. If treated with caustic potash at 190 C., 

 it yields a body phylloporphyrin, C 16 H 18 N 2 0. Both haematoporphyrin 

 and phylloporphyrin yield on reduction a body called haemopyrrol. 

 It has been suggested that haemoglobin is synthesized out of the chloro- 

 phyll eaten in the food. 



From haematin, by the action of acids, haematoporphyrin and a 

 body termed mesoporphyrin are obtained. By reduction of haema 

 toporphyrin, haemopyrrol (C 8 H 13 N) is obtained, and by oxidation ar.d 

 treatment with caustic potash methylethylmaleic acid anhydrk'e 

 (C 8 H 8 5 ). Both these bodies can also be obtained by the splittirg 

 of chlorophyll. 



Oxyhaemoglobin 



^ 

 Haematin 



4- 



Haematoporphyrin 



Mesoporphyrin Hsemopyrrol (C 8 H 13 N) 



J^ 



Methylethylmaleic acid 



anhydride (C 8 H 8 5 ) 



The pigments of the bile (bilirubin and biliverdin), the pigments 

 of the faeces (stercobilin), one of the pigments of the urine (urobilin), are 

 derivatives of haematin, and, like haematoporphyrin, contain no iron. 



