128 EIGHTH REPORT — 1838. 



Dr. Dalziel describes an apparatus for ascertaining the practicability 

 of promoting artificial respiration, as a remedial means in certain states 

 of the system. 



Some time ago it occurred to tlie author, that certain diseases, accom- 

 panied witli depression, might be mitigated, and other depressed states 

 of the system effectually remedied, by immersing the limbs and trunk 

 of the body in air which should be alternately rarefied and recon- 

 densed, at the same time allowing the patient to inhale the air of the 

 external atmosphere ; the rarefaction and recondensation to correspond 

 with the motions of inspiration and expiration respectively. By this 

 means, it was expected the function of respiration might be directly sup- 

 ported and the general system invigorated. Inspiration being assumed 

 to be tlie more laborious pai-t of the process of respiration, and expira- 

 tion to require little or no effort, it is the former part of the process that 

 in depressing affections requires assistance. 



The degree of assistance which might in these cases be afforded, could, 

 Dr. Dalziel supposed, be tested by experiments on persons in health, 

 wth apparatus of very simple construction. That which he made use 

 of consisted of an air-tigiit box, large enough to contain the person to 

 be experimented on (the head and neck excepted,) in a sitting posture, 

 and a pair of circular bellows inside, which were used as a forcing air- 

 pump. The bellows ^vere worked from without by a piston rod, and 

 the air which at every stroke they discharged was prevented by a valve 

 from returning. In the side of the box were two small convex windows ; 

 one for the admission of light, the other for allowing an attendant to 

 inspect tlie surface of the body during the experiment. 



When, by this apparatus, the pressure of the air was, to a certain extent, 

 removed from the parietes of the chest, the feelings of exertion and re- 

 pose attending respecti\'ely on inspiration and expiration were completely 

 interchanged. The comparatively heavy air of the external atmosphere, 

 which the person breathed, rushed along the air-passages and distended 

 the chest ^lithout effort. There was a pre\'ailing disposition to inspire. 

 When the respiratory muscles ^^'ere relaxed, the chest remained perma- 

 nently distended, and a sensation of fulness of this cavity was distinctly 

 experienced. Expiration on the other hand became difficult and labo- 

 rious. The feeling in the chest attendant on the effort was analogous 

 to that M-hich is experienced in ordinary circumstances during inspira- 

 tion, while supporting with the hands a heavy weight upon the breast, 

 and attempting to elevate it. The voice in the mean time became so 

 weak as to be almost inaudible. 



In order to produce the results above-stated, the air contained in the 

 box was rarefied by abstraction of about one-nineteenth of its volume. 



Dr. Dalziel suggested the application of this apparatus in all diseases 

 and affections of the system in which the functions of respiration and 

 circulation require to be roused or supported. 



A model of more refined apparatus to perform the same effects, and 

 several testimonials respecting the period of the invention, (1832,) were 

 presented to the Section. 



