411 
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Report of Experiments on the Physiology of the Lungs and 
Air-tubes. By Cuarues J. B. Wixttiams, M.D., F.R.S, 
WHEN at the request of the Medical Section of the British As- 
sociation, I undertook three years since to investigate experi- 
mentally several doubtful points respecting the properties and 
offices of parts of the respiratory apparatus in the higher classes 
of animals, I hoped to be able to include in the inquiry the che- 
mical process of respiration, and the vital effects of its interrup- 
tion. Professional engagements having obliged me to relinquish 
these points, I have restricted my attention to others more im- 
mediately bearing on practical medicine. The chief of these are 
the contractility and sensibility of the air-tubes and lungs. 
It has long been a matter of controversy whether the lungs 
ind air-tubes are more than passive in the motions of respiration ; 
whether they possess any self-contracting or expanding power, 
independent of the muscles which affect the capacity of the 
chest. Different writers, both ancient and modern, have main- 
tained opposite opinions. Laennec, after Sennert, Bremond 
and others, attributed to the lungs both a self-contractile and 
self-expansive power, in addition to their mechanical or elastic 
properties. Haller, on the other hand, was led by experiment 
to deny that any independent vital motions are exhibited by the 
lungs of animals, corresponding with those of respiration; and 
Miller has confirmed these negative results. Within the last 
few years certain writers in this country and in France*, have 
denied altogether the muscular contractility of any part of the 
air-tubes below the larynx. 
These negative observations are in opposition to the generally- 
received opinion, derived chiefly from the anatomical researches 
of Reisseissen, that the circular fibres of the air-tubes, from the 
trachea to their terminations, are muscular. Very few at- 
tempts have been made to solve this problem by experiment. 
Varnier and Wedemeyer only succeeded in exciting partial con- 
tractions in the smaller bronchi; but after all their results, 
Miller concludes that “ it is remarkable that there exists at pre- 
sent no direct proof of the contractility of the wnuscular fibres 
of the trachea and its branchest.”’ 
I need scarcely remark, that this subject is by no means one 
of merely speculative interest. Much of the pathology and 
* MM. Trousseau and Belloc, Dr. Geo. Budd, &c. 
+ Elements of Physiology, translated by Baly. 
