32 Society for Experimental Biology and Medicine. 



these signs of pain were aroused, was found by experiments in 

 which partial cross-sections of the cord were made, to run not in 

 the posterior, but in the lateral columns. The pain pathway from 

 either side of the body runs up both halves of the cord, but more 

 largely up the opposite half. 



31. " An experimental study of the cause of shock " : WILLIAM 



H. HOWELL. [Presented by S. J. MELTZER.] 



Professor Howell's experiments were made upon dogs anaes- 

 thetized with morphin and ether, and brought into a condition of 

 shock by operations of various kinds. Blood-pressure records 

 were obtained in the usual way during the experiment. The fol- 

 lowing general conclusions were reached : 



I. The most important and dangerous feature of severe shock 

 is a long continued, practically permanent fall in blood-pressure 

 to about 20 mm. to 40 mm. of Hg. This condition is designated 

 as vascular shock and is due to a long lasting loss of activity of 

 the vasoconstrictor center. 



2. A second important result of shock is a very rapid and 

 feeble heart-beat. This condition is designated as cardiac shock ; 

 since, although it may result secondarily from the permanent fall 

 in blood-pressure, it may also occur quite independently of the 

 vascular shock as a primary result of the operations. Cardiac 

 shock, so far at least as the rate of beat is concerned, is due to a more 

 or less permanent loss of activity of the cardioinhibitory center. 



3. Intravenous infusions of alkaline salt solutions (NaCl, 0.6% 

 — Na 2 C0 3 , 0.5%) cause a rise of pressure by increasing the force 

 of the heat-beat. The effect is more durable than with salt solu- 

 tion alone and may be renewed by repeating the injection. 



4. The fundamental cause of vascular and cardiac shock is not 

 exhaustion of the vasomotor and cardioinhibitory centers from 

 over activity, but a more or less permanent inhibition of these 

 centers from excessive stimulation of the inhibitory paths. 



Sixth meeting. 1 



Bacteriological Laboratory of the Department of Pathology of 

 Columbia University, at the College of Physicians and Surgeons. 

 April 20, 1 po 4. 



1 Reprinted from Science, 1904, xix, p. 828; American Medicine, 1904, vii, p. 

 789; Medical News, 1904, Ixxxiv, p. 1101. 



