1894.] On the Coagulability of the Blood in Vivo. 279 



VIII. " On the Influence of Carbonic Acid and Oxygen upon 

 the Coagulability of the Blood in Vivo." By A. E. WRIGHT, 

 M.D. (Dubl.), Professor of Pathology, Army Medical School, 

 Netley. Communicated by AUGUSTUS D. WALLER, M.D., 

 F.R.8. Received February 8, 1894. 



I have, in the course of previous researches on hlood coagulation,* 

 had occasion to suggest that the phenomena with which I was 

 dealing might be explained in a very simple manner by assuming 

 that carbonic acid gas exercised a favourable influence on the oc- 

 currence of blood coagulation. The present research consists of an 

 examination of the hypothesis in question. 



The method of experimentation employed consisted in determin- 

 ing the alterations of blood coagulability which occurred in animals 

 when alterations were effected in the respiratory gases with which 

 they were supplied. 



Details of the Method of Experimentation employed. ' 



The animals experimented upon were dogs and rabbits. The 

 animals were in all cases tracheotomised under the influence of 

 ether (rabbits) or of a mixture of ether and chloroform (dogs). In 

 the case of the dogs, the animals were kept under the influence of 

 the chloroform and ether during the whole course of the experi- 

 ment. In the case of the rabbits, the repeated inhalations of 

 carbonic acid and other gaseous mixtures served to keep up the 

 anaesthesia. The tracheotomy tubes were connected up with a 

 "J"-tube ; one limb- of the ""["-tube was fitted with a Speck's intes- 

 tinal valve (made of rabbit-gut), and allowed of free expiration into 

 the outer air. The other limb of the "["-tube was connected up at 

 pleasure with reservoirs (4,000 c.c. capacity) of pure gases or gaseous 

 mixtures standing over water. The water was carefully kept at the 

 same level inside and outside of the reservoirs during the whole 

 Dourse of an experiment. A convenient check upon this was 

 afforded by the regular opening and closing of the intestinal valve. 



The blood for the coagulability estimations was obtained from the 

 ir. In the case of the rabbits, the blood was invariably drawn off 



)m the central artery of the ear. Only rabbits with full ear 

 rteries were employed in the experiments. 



The blood coagulability determinations were made by the method 



capillary coagulation tubes recentlyf described by me. The method 



* ' Journ. of Physiol.,' vol. 12, No. 2 ; ' Roy. Irish Aoad. Proc.,' 3rd Series, yol. 2, 

 To. 2 ; ' Roy. Soc. Proc./ February, 1893. 

 t ' Brit. Med. Journ.,' July 29th, 1893, and February 3rd, 1894. 



