106 THE ADRENALS AND THE RESPIRATORY BLOOD-CHANGES. 



of dilation of the central vascular trunks, contraction of the 

 peripheral capillaries, etc. are self-evident. 



That the adrenals are involved is further sustained by the 

 observation of Lauder Brunton that if the descending aorta 

 be tied high up no perceptible fall of pressure is produced by 

 the amyl salt for some time. It is to be presumed that the 

 ligation was practiced above the suprarenal vessels. "In lower 

 animals," says Wood, "the first stage of the action is like that 

 just described in man. After this the breathing becomes 

 violently hurried and panting, progressive muscular weakness 

 and diminution of reflex activity ensue, and finally death from 

 failure of respiration. ... A very peculiar symptom is 

 that a long time before death both the arterial and the venous 

 blood become of a nearly uniform chocolate color." The simul- 

 taneous occurrence of these phenomena clearly defines the mor- 

 bid process. The chocolate-red blood, though still able to 

 absorb oxygen, does so "very imperfectly"; hence the "violently 

 hurried and panting" breathing to compensate by the number 

 of respirations for the lessened oxidation. The general metabo- 

 lism, impaired through imperfect hgemic respiration and there- 

 fore lessened oxidation, accounts for the rest: a symptom- 

 complex with the suprarenal glands as starting-point. 



In view of all these facts, the manner in which metha3mo- 

 globin is formed in the organism after poisoning seems to us 

 to be as follows: The adrenals supply an oxidizaUe principle to 

 the Hood. When a poison causes insufficiency of these glands, a 

 compound inferior in its oxygen-absorbing power to haemoglobin is 

 formed, namely: methcemoglobin. The presence of this pigment 

 in the blood is attended with more or less marked impairment of 

 the respiratory function. 



H^MATOPORPHYRIN. How is this pigment formed in the 

 organism as a result of poisoning? Sulphonal and trional have 

 furnished, of all toxics, the greatest number of recorded cases 

 of hgematoporphyrinuria, and will therefore be used as the basis 

 of this analysis. 



Hsematoporphyrin is stated by Garrod 75 to be present in 

 normal urine in minimum quantity, in solid excreta, and 



76 Garrod: Lancet, Nov. 10, 1900. 



