ADRENAL INSUFFICIENCY AND BLOOD-DISINTEGRATION. 119 



fore, of obtaining hsematoporphyrin as end-result, we obtain 

 hydrobilirubin, the reaction being approximately as follows: 



2(C 32 H 36 N 4 6 ) - 2 + 4H 2 = 2(C 32 H 36 N 4 5 .2H 2 0) 



Bilirubin. Hydrobilirubin. 



Hydrobilirubin, as is well known, is usually termed "febrile 

 urobilin" though it often appears in diseases in which fever 

 does not occur. 



All these facts suggest another conclusion: i.e., that 

 hcematoporphyrin, bilirubin, hcemato'idin, and its other isomers, 

 as haemoglobin derivatives, are restored to the pulmonary cir- 

 culation ~by reabsorption from the intestine, and again used in 

 the building up of haemoglobin. This is sustained by what 

 evidence is available. It also satisfies the requirements of all 

 the experiments referred to in Garrod's paper, which the other 

 hypotheses outlined therein failed to meet. 



The reduction to a single pigment of all the isomers of 

 hoematoporphyrin is not only important from the clinical stand- 

 point, but it will assist us in elucidating various features of the 

 question in point: i.e., the relationship between the adrenals 

 and the respiratory function. Especially does this apply to 

 haematoidin, one of the pigments referred to. "In old blood- 

 clots in the body/' says Professor Foster, "the haemoglobin 

 of the clot becomes in time transformed into an iron-free 

 body which has been called heamatoidin, but which, both in 

 composition and reactions, appears to be identical with bili- 

 rubin." Again, he refers to the identity of both compounds 

 in the following words: "Virchow 89 has described the gradual 

 changes in old blood-clots, such as those of cerebral haemor- 

 rhage, which lead to the presence of the so-called haematoidin- 

 crystals. Though these have not been obtained in sufficient 

 quantities to enable their composition to be finally fixed by a 

 chemical analysis, still, the identity of their crystalline form 

 with that of bilirubin, and the fact that they both give the 

 same play of colors when oxidized, as in Gmelin's test, justify 

 the assumption that hcemato'idin and bilirubin are identical." 90 



The presence of hsematoi'din in conditions of advanced 



89 Virchow: Archiv fur path. Anat, Bd. i, S. 383. 



90 The italics are our own. 



