104 THE ADRENALS AND THE RESPIRATORY BLOOD-CHANGES. 



doses of these drugs. Nitroglycerin and amyl nitrite have both 

 been found to act similarly, in many ways, by Lauder Brunton, 

 Tait, Murrell, Hay, and Henocque. As the latter drug is the 

 more completely reviewed by Wood, it will be used as the basis 

 of this inquiry. "When," says this author, "an animal inhales 

 amyl nitrite, the arterial and venous blood soon become of a 

 nearly uniform hue, which resembles somewhat that of normal 

 venous blood, but is quite distinct from it, having a chocolate 

 tint." Are we dealing with mere deficiency of oxidation or 

 accumulation of carbonic acid? Evidently not, since Wood 

 states that "this chocolate-colored blood does not assume the 

 arterial hue when shaken up with the air." According to Gamgee, 

 the nerve-centers are directly affected; but we have already 

 ascertained that the respiratory centers are not the source of 

 phenomena that occur in this connection, and, as shown below, 

 the effects of the toxic occur notwithstanding division of the 

 spinal cord. As the splanchnic nerve is that connected with 

 the adrenals, the sympathetic system must be the one morbidly 

 influenced by the poison. An important fact suggested by this 

 nervous origin, however, is that the direct haBmolytic influence 

 of the poison, thought generally to exist, is set aside, and that 

 we are normally brought to the only agency available to ac- 

 count for the process: i.e., the adrenals. But why does the 

 chocolate methaBmoglobinic blood not assume the arterial hue 

 by exposure to air? Can we concede that whenever, in the 

 organism, the haemoglobin-molecule becomes dissociated, its 

 constituents are all eliminated with the excretions? Evidently 

 not. Even in chlorosis, in which haamic respiration is greatly 

 impaired, it is not, of course, abolished, and the components 

 of the hemoglobin-molecule must, in a measure, hold together, 

 though loosely combined. But evidently some constituent 

 capable of taking up oxygen must be missing in the metha3mo- 

 globinic blood referred to, to account for its inability, when 

 exposed to the air, to become arterialized. Now, the adrenals 

 being rendered insufficient by the drugs mentioned plus the 

 known affinity of their secretion for oxygen, clearly suggest, 

 it seems to us, that, if the methannoglobmic blood could not 

 be oxidized outside the body, it is because it lacked the supra- 

 renal secretion. This tends to show that the suprarenal secre- 



