TRANS ACTlO?JS Of Tllfi SECTIONS, l29 



Oil an Improved Acoustic Instrument. Bij Dr. Yelloly, F.R.S. 



This communication was illustrated by a model of the instrument 

 wliicli Dr. Yelloly proposed for the purpose of assisting in cases of 

 partial deafness. Allusion was made to the very defective nature of our 

 present instruments, both as to utility and conveniency, and the import- 

 ance of appointing some experimental investigation on the subject *. 



On the Action of various Substances on the Animal Economy, when 

 injected into the Veins. By J. Blake. 



The author described a number of experiments with various sub- 

 stances, and their effect on the vascular system, as measured by an in- 

 strument which he termed a Haemadynameter, formed by a glass tube, 

 bent at an angle. One limb of this tube being attached to a scale, 

 allows of measuring the height to wh\ch a column of mercury is raised 

 by the action of the current of blood in the artery, into which the ex- 

 tremity of the other branch is introduced. The substances introduced, 

 in solution, into the veins, were divided into three classes according to 

 their effects. In \!wq first were those which produced death, by directly 

 acting on the contractility of the heart, amongst which were nitrate of 

 potassa, arseniate of potassa, sub-carbonate of soda, biniodide of arsenic, 

 oxalic acid, and solution of galls ; all these acted locally on the heart, 

 and agreed in effecting a change in the colour of the blood, turning it 

 black, probably by forming definite combinations with its constituents. 

 A remarkable difference was observable in the effects produced by the 

 same substances when absorbed from the stomach. In the second class 

 were those substances which acted directly on the nervous system ; 

 such were strychnia, hydrocyanic acid, and couia. And in the third 

 were those producing death by affecting the capillary circulation ; such 

 were tobacco, euphorbium, and digitalis. The last two classes of sub- 

 stances did not produce any change on the composition of the blood. 

 Several other substances were experimented with, not falling under 

 the above classes, such as morphia and canthai'ides, the effects of 

 vv'hich were the same, and nitric acid : when the latter was injected 

 into the vein, the column of mercury in the instrument fell from seven 

 inches to one ; and after death, the right side of the heart was distended 

 with solid blood. 



On an Improved Stethoscope. By A. B. Granville, M.D. 



By this invention the patient may be examined without the necessity 

 of his rising, and the necessity of having the pi'actitioner's head im- 

 mediately' parallel to tlie part examined is avoided. These advantages 

 are effected by the addition of a half ball-and-socket joint attached to 



* A recommendation to this effect was adopted by the General Committee. 



VOL. VII. 1838. K 



