RESPIRATORY REGULATION OF THE CO, CAPACITY 
OF THE BLOOD. 
IV. THE SEQUENCE OF TRAUMA, EXCESSIVE BREATHING, 
REDUCED CO, CAPACITY, AND SHOCK. 
By YANDELL HENDERSON anp H. W. HAGGARD. 
(From the Physiological Laboratory, Yale Medical School, New Haven.) 
(Received for publication, December 31, 1917.) 
The term ‘“‘shock”’ has come to be applied not only to the most 
diverse sorts of functional depression following trauma, but also 
to nearly any experimental method (no matter how artificial) for 
causing circulatory failure. : 
The common procedure for the production of shock experi- 
mentally in dogs is to expose and manipulate the abdominal 
viscera under morphine anesthesia. The bearing of such radical 
experiments on shock in man can be accepted only with 
considerable reserve. This is important in considering experi- 
mental work on shock because of the fact that, as Mann! has 
pointed out, with the exception of certain experiments perforn ed 
some years ago in this laboratory, the procedure of exposure and 
manipulation of the abdominal viscera has been almost the sole 
method by which ‘‘shock”’ has been induced experimentally. 
In some experiments, of which a preliminary notice was pub- 
lished some months ago by Prince and ourselves,” it was found 
that after irritation of the abdominal viscera a marked reduction 
of the CO, capacity of the blood occurred. In these experiments 
we intentionally induced excessive (natural) breathing. 
Recently Cannon* has reported that in wounded soldiers in 
shock the ‘‘alkaline reserve”? or CO. capacity of the blood is 
1 Mann, F. C., Bull. Johns Hopkins Hosp., 1914, xxv, 205. 
2 Henderson, Y., Prince, A. L., and Haggard, H. W., J. Am. Med. Assn., 
1917, lxix, 965. 
’ Cannon, W. B., Reports to Committee on Physiology, National Re- 
search Council, Am. J. Physiol., in press. 
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