Sudden Changes in Pressure 863 



which is curled up, turns backwards and bites his hind legs and 

 thighs with a kind of fury. 



After 5 minutes, relatively calm; the left pupil dilated inordinately; 

 almost complete paraplegia. Defecation by intestinal contraction, the 

 anal sphincter not being paralyzed. Urination; no blood or sperm. 

 5:30. I show the animal to the Society of Biology; the paraplegia is 

 complete as to movement and sensitivity. The pupils are in their 

 normal state. 5:45. Apparent improvement; the left leg is sensitive, 

 and the animal moves it a little, and when I support it, even leans on 

 it a little; nothing in the right leg. 6:15. The right leg recovers a 

 little in its turn; the tail begins to be sensitive. 



June 23. The paraplegia has become complete again, and has even 

 spread a little into the lower dorsal region. The following days, paral- 

 ysis still more complete and extending a little higher. Dies June 26, 

 the bladder distended; it could not be made to urinate; it ate. 



Autopsy. All the spinal marrow is softened a little; it is diffluent 

 below the cervical enlargement. At this precise point, it is a little 

 yellowish, and contains a little altered blood and some granular bodies 

 in the process of formation; the veins of the meninges contain a mix- 

 ture of air and blood; air escapes from the vessels of the spinal cord. 

 Sugar in the liver, a little in the urine, which also contains a little 

 blood. 



E. Experiments Made on Dogs. 



Experiment DXXVII. May 17. Dog weighing 4 kilos. Pressure 

 raised to 4 atmospheres. After about Va of an hour, opened the large 

 cock suddenly; decompression in less than 2 minutes. The animal is 

 in good shape. 



Experiment DXXVIII. June 18. Small dog. Taken in one hour to 

 10 atmospheres; stays there about 1 hour; decompressed in 3 minutes. 

 The animal cannot get out of the apparatus; there are no other move- 

 ments than those of respiration; constant cries of pain. 



Placed on the autopsy table, gas is observed in the jugular which 

 has been exposed. Through the jugular a cannula is passed into the 

 right heart, from which is extracted 33.9 cc. of gas containing 20.8% 

 of CO. and 79.2% of nitrogen, with some traces of oxygen. The right 

 heart and the veins are full of gas and frothy blood; the same thing 

 is true of the veins of the pia-mater and the choroid plexuses. Stom- 

 ach much distended by gases. 



Experiment DXX1X. July 9. Dog weighing 12 kilos. 

 1:45: taken to 5 atmospheres; left 30 minutes under a current of 

 air. Decompressed in 2 minutes. No immediate or delayed symptom. 



Experiment DXXX. July 13. Dog which has lost much blood. 

 Taken to 6 atmospheres and decompressed in 2 minutes. The animal 

 drags its hind legs and walks on its nails; after an hour, walks better, 

 but lies down again as soon as we stop stimulating him. Better {he 

 next day. 



