Ktfeet of 'I'liyroid-Fet'ilinj; on tlu' Suprareiml.s 49 



received the amount «)f thyroid dt'sired. The control aninmls wf-n- kept 

 in several ca«;e.s in the first experiment (Table I.), and no addititni was 

 made to their diet of bread and milk. 



1 n .1 .second series of experiments, recorded in TahlrH III. and IV.. ten 

 male rats taken from two litters born on the same day were utilised. 

 Five of them, avera^nn*,' 7.S <.jrm. each in body-wei;;ht, received 0*2 j^rm. 

 fresh ox thyroid daily for from 23 to 2(J days. The other five, which 

 averai^ed the same weifjht, received ()-2 <,'rm. fresh ox tlesh daily for the 

 .same period. All these animals were kept under identical conditions. 

 Kach was in a separate metabolism cage and received tiie same diet of 

 bread and milk, with which the thyroid was mixed in the one case, and 

 the ox Hesh in the other. 



At the close of the experiment the rat to be examined was decapitated, 

 and the suprarenals di.ssected out, cleared of the surrounding^ fat, and 

 wei<^lied. The suprarenals were then minced and pounded in a mortar, 

 extracted with decinormal HCl, boiled with the addition of 10 per cent, 

 sodium acetate, cooled and filtered. The liltrate, with the addition of 

 Folin's reagent and saturated sodium carljonate, was made up to 50 c.c. 

 with distilled water. The colour resulting was then compared in a 

 Duboscj colorimeter with the colour produced by a solution of uric acid 

 containing 0"5 mg. per cent. This is half the strength recommended by 

 Folin (H), but for measuring the small amount of adrenalin in the rat's 

 suprarenals is more suitable than the usual standard. The depth of the 

 uric acid solution was set at 20 nnn. in the colorimeter, and the depth of 

 the suprarenal solution regulated until of the same tint. The amount of 

 adrenalin in the solution was then determined, taking the colour produced 

 by the adrenalin as being three times as inten.se as that given by the same 

 strength of uric acid. E. Merck's extra pure uric acid was used as the 

 standard, and it is assumed in these experiments that what Folin found 

 true of Kahlbaum's pure uric acid is also true of E. Merck's. The uric 

 acid solution was prepared according to the directions given by Folin, 

 and was never more than a day old when used. It deteriorates rapidly, 

 and shows considerable loss of strength three days after being made up. 



All the (juantitative measurements of adrenalin given in this paper 

 have been made by Folin's method. Several control experiments have 

 been carried out in which the solutions have been tested by Elliott's 

 method on the blood-pressure of a pithed cat. Parke, Davis <Sr Co.'s pure 

 adrenalin powder was used to make up the standard solution. It was 

 diluted to a strength similar to that found in the extract of suprarenal 

 tested by Folin's method, and both were injected intravenously. The 

 action of the pure adrenalin solution on blood-pressure was rather greater 

 than that of the extract of suprarenal. It cannot be said that the controls 

 were quite satisfactory. This was chiefly because, in the absence of any 

 assistance, the experiment took a considerable time. The adrenalin 

 solutions were made up much later than the extract tested by Folin's 



VOL. XL, NO. 1. — 1917. '* 



