904 



SCIENCE. 



[N. S. Vol. V. No. 128. 



rose gradually to a maximum above the 

 normal pressure and then declined more 

 slowly. In these experiments the maximum 

 rise of pressure varied from 20 to 60 mms. 

 Hg. and the maximum reduction in pulse 

 rate varied from 40 to 60 per cent, of the 

 rate existing before the injection. "When 

 the vagi were cut, or the animal was atro- 

 pinized, the injections caused a rise of pres- 

 sure, followed in some cases by a temporary 

 fall, and then a more gradual but pro- 

 nounced rise, together with a slower and 

 more powerful heart beat. Under these 

 conditions the maximal rise of pressure 

 varied from 50 to 90 mm. Hg., while the 

 maximal slowing of the pulse ranged from 

 17 to 35 per cent, of the rate before injec- 

 tion. Animals deeply under ether alone 

 behaved in this respect like animals with . 

 the vagi cut. The slowing of the heart 

 caused by extracts of the infundibular lobe 

 seems, therefore, to be due in part to an 

 effect upon the cardio-inhibitory center and 

 in part to a peripheral effect, differing in 

 this latter respect from suprarenal extracts. 

 The effect upon the blood pressure seems to 

 be due mainly to a peripheral effect, since 

 it can be obtained readily in animals with 

 the cord severed from the medulla and with 

 part of the thoracic cord extirpated. As 

 compared with extracts of the suprarenal 

 bodies the effect of these extracts are char- 

 acterized by their long duration, and the 

 longer interval of time that must be allowed 

 in order to obtain a similar effect from a 

 second injection. 



A Contribution to the Physiology of the Supra- 

 renal Capsules. G. P. Deeyee. 

 The most striking effects of the injection 

 of extracts of the suprarenals into blood 

 vessels are general vaso-constriction with 

 rise of blood pressure, slowing of pulse 

 with intact vagi, and acceleration of pulse 

 with vagi cut or paralyzed by atropin. 

 Is the active substance contained in such 

 extracts a product of the normal activity of 



the gland cells, i.e., a, true internal secretion, 

 or the result of post-mortem changes ? If 

 the former a greater amount of it would be 

 contained in blood coming direct from the 

 gland than in blood taken from some other 

 systemic vein, and this increase might be 

 detected by the effects produced by intra- 

 venous injections of adrenal blood as com- 

 pared with the effects of similar injections 

 of blood from other veins. The author has 

 made a series of such experiments on ten 

 ansesthetized dogs. Femoral blood and 

 adrenal blood were alternately injected into 

 the jugular vein in quantities ranging from 

 5 c.c. to 40 c.c, either into the same animal 

 from which it had been taken or into a 

 fresh animal. In every case the adrenal 

 blood gave an appreciable rise of pressure,, 

 in some cases exceeding 40 per cent., while 

 the inhibition of the heart before section of 

 the vagi, or the acceleration after atropine 

 injection, were practically constant phe- 

 nomena. The variation in the extent of 

 the effects must probably be ascribed to 

 differences in the secretory activity of the 

 gland in the different dogs. Furthermore, 

 in general, the effect was greater the 

 slower the outflow, from the adrenal vein, 

 and apparently gi-eater when the injec- 

 tion was into a dog other than the one 

 yielding the adrenal blood. Blood from 

 the femoral vein gave negative results. 

 Gases of the Blood during Nitrous Oxide Ances- 



thesia. G-. T. Kemp. 



The author's previous experiments have- 

 shown that when enough air or oxygen is 

 mixed with nitrous oxide to keep an animal 

 alive, ansesthesia can be maintained for a 

 considerable length of time without risk of 

 life to the animal. When nitrous oxide is 

 replaced by nitrogen, the ansesthesia passes 

 off. This shows that nitrous oxide pos- 

 sesses specific anaesthetizing properties not 

 possessed by nitrogen. 



A more thorough knowledge of the con- 

 dition of the system during nitrous oxide 



