carmine-red body. We have as yet made no experiments with this pig- 

 ment except to note that it is but slightly soluble in dilute alkalies 

 and insoluble in dilute acids, and that iodine destroys the color. Our 

 method appears to make the further study of this substance possible. 



The coniine-like substance we have secured in the form of its hy- 

 drochlorate, and with it we have made certain studies which will be 

 published at a later date. 



Characteristics of the Blood-Pressure-Raising Constituent 



as obtained by decomposing its 



Benzoyl Compound 



We have now obtained the active principle in the form of a sul- 

 phate. As thus far isolated it is a hygroscopic, straw-colored residue 

 which tends to crystallize on standing over sulphuric acid, agglomer- 

 ates of small crystals forming on the edge of the bowl and the entire 

 residue taking on a semi-crystalline appearance. This sulphate does 

 not contain the volatile coniine-like substance, nor do we find the 

 carmine-red pigment which falls out on the addition of an alkali. 

 Alkalies no longer liberate the coniine-like substance, nor do they 

 throw out the red pigment, but they cause a brownish discoloration, 

 and on heating, alkaline vapors, probably ammonia, are given off. 



Our sulphate is very active physiologically. A small quantity suf- 

 fices to raise the blood-pressure and it is therefore evident that we 

 have isolated the active principle but slightly contaminated with other 

 substances. 



A final product even more active in small quantities is that whose 

 action is shown where the mercury is driven out of the manometer. 

 This more active compound still contains much of the coniine-like 

 substance, and at once throws out the carmine-red pigment on the 

 addition of alkalies. The sulphate of the coniine-like substance does 

 not, as we have seen, raise the blood pressure; it therefore remains 

 for us to consider whether the carmine-red substance Avhich is pre- 

 cipitated on the addition of alkalies, either alone or in conjunction 

 with small quantities of oxidizing agents, has any physiological sig- 

 nificance or stands in any chemical relation to the blood-pressure- 

 raising constituent. We incline to the opinion that this substance, 

 which in the original aqueous solution of the gland gives with iodine 

 water the "teinte rose-carmin tout a fait remarquable" of Vulpian, is 

 in nowise connected with the blood-pressure-raising constituent. We 

 have repeatedly removed or destroyed this substance by boiling solu- 

 tions containing it with strong ammonia or with sodium hydrate, 



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