720 Experiments 



compared to those in which no such precaution had been taken, 

 allow me to state that in the latter the influence of the carbonic 

 acid was quite negligible; that will be explained naturally, when 

 we discuss poisoning by carbonic acid in Chapter VIII. 



Here now is the report of a certain number of experiments. 



Experiment CCLXXVIII. November 16. Black dog, short-haired, 

 new subject, weighing about 12 kilograms. 



It is fastened on its back, and in its trachea is inserted a metal 

 tube, at the end of which is a rubber tube considerably narrower. 

 Respiration is carried on in series of extreme frequency, separated 

 by a few intervals of calm. 



At the end of about a half-hour, the rectal temperature is 36° 

 (in a healthy dog the same thermometer gives 38.5°). 



Then from the left carotid 35 cc. of blood is drawn, which is imme- 

 diately taken to the pump for extracting gases .... A 



The dog is next placed in the compression apparatus; to the tube 

 in its trachea is then fitted a rubber bag containing oxygen; then the 

 animal is fastened as explained above. 



Pressure is begun at 3:56. 



At 4:21, the pressure is 5 atmospheres; I draw 38 cc. of very red 

 blood, not letting gas escape . . . . B 



At 4:40, at 7 atmospheres, drew 31 cc. of very red blood, in which 

 escape of gas is at least doubtful . . . . C 



Pressure is raised to 8 atmospheres, and at 4:45 decompression is 

 made suddenly in 3V2 minutes. 



The animal is immediately withdrawn from the apparatus; there 

 are no free gases in either the arterial or the venous blood; the heart 

 sounds are normal, without any gurgling indicating the presence of 

 gas. The rectal temperature is 30°. There has been an evacuation of 

 fecal matter, and the mouth is full of froth. 



The paws are much stiffened; when the animal is unfastened, he is 

 in very pronounced opisthotonos; the whole body is in tonic convul- 

 sion. Fecal matter continues to be discharged. The eye closes when 

 the cornea, but not when the conjunctiva, is touched; the pupils, much 

 dilated, do not contract in light. 



The arterial pressure in the carotid varies between 9 and 12 

 centimeters. 



The symptoms continue to increase in intensity. About 5 o'clock, 

 the convulsions are extremely violent; in the midst of continuous 

 stiffenings, there appear clonic convulsions of the limbs, the neck, and 

 the jaws. The eyes are convulsed. The penis is so retracted that to 

 catheterize the animal the prepuce has to be slit its whole length; no 

 urine in the bladder. The animal froths terribly. 



About 5:30, the temperature is 29 degrees. Vomiting begins. The 

 convulsions appear like fits, with no real rest in the interval; it appears 

 much like successive strychnine attacks, except for the almost com- 

 plete permanency of the stiffenings and the opisthotonos. Clonic 

 convulsions are caused by touching the animal, by hitting the table, 



