A STUDY IN MORBID A ^^ D NORMAL P II Y S I O L O G Y. 45 



The results in all of these experiments save one are in accord, and in the 

 exceptional case the difference is one of degree and not of kind. Neverthe- 

 less the variance is a rather wide one. llow it is to be acconuied for it is difficult 

 to decide. My own belief is that the experiment was not accurately perfornu-d. 

 It was about the third or fourth time I had ever used the calorimeter, and it is very 

 possible that some slight misreading of thermometers may have occurred. A'min, 

 the profound disturbance of breathing may have affected the result, or I may not 

 have completely severed the cord. In every experiment there was diminished li<'at 

 production following the section, the se\eral percentages of loss being as follows : 

 in the 25th experiment, 50 per cent.; 26th, forty-eight hours after section, 41 per 

 cent.; 27th, 10 percent.; 28th, 18 per cent.; 29th, 83 per cent.; 30th, 40 per 

 cent.; 31st, 28 per cent.; 33d, 41 per cent ; average percentage of loss hi tlie 

 seven experiments (omitting the 27th) 43 per cent. 



Leaving out of sight the 27th experiment I think we m;iy consider the following 

 proposition as demonstrated. 



Section of the spinaJ enrd above (he ori<jin of the splanchnic ncnvs, is usv all i/ fol- 

 lowed hy an immediate very decided increase in the amount of In at dissipated from 

 the hody, and also hy a decided iesscning of the amount of heat produced. 



The known influences which follow section of the spinal cord, capable of affect- 

 ing the production of heat, are vaso-motor paralysis, lessening of the cardiac force, 

 muscular quiet, diminished respiration, lowering of tem])evature. Of these, dimin- 

 ished respiration may be left out of the question, because lessened production of heat 

 follows even when the cord has been cut so low down as not to embarrass respiration ; 

 muscular quiet seems also of little importance, because the animal in the present 

 series of experiments was always confined in a small dark chamber, and was usually 

 perfectly quiet in the first portion of the comparative experiment, i. e., before sec- 

 tion. The lowering of the cardiac force by section of the cord is so indirect and 

 so slight that it is hardly probable that it is a factor of much importance. So that 

 the conclusion seems forced upon us that the primary cause of the lessened heat 

 production is vaso-motor' paralysis, which probably acts directly, and also indirectly 

 by causing an excessive loss of heat, and such a lowering of the internal temperature 

 as to check chemical reactions in the body. How general vaso-motor paralysis 

 acts directly upon heat production is easily perceived. A local vaso-motor palsy 

 causes increased and quickened circulation in the part; but a general dilatation ot 

 all the vessels produces a sluggishness in the movements of the blood in all parts 

 of the body. It is universally recognized that excessive activity of the circulation 

 in a part tends to produce excessive chemical action, and it seems a logical in- 

 ference that lessened circulation predisposes to lessened chemical activity. 



In order to determine whether the chief role in the diminution of the production 



' With these facts known, the reason why iu Experiments 42 and 43 there was not increased heat 

 dissipation becomes apparent. In both cases there was a diaiinisiied production of lieat, and in one 

 case owing to the great protection of tlie surface of the body by tlie tliick coat, and in tlic other 

 case to the section of tlie cord being below the centres which supply the vessels of the surface of the 

 body, the customary rush of heat from within the body to without did not occur, and the diminished 

 production was able to make itself felt in the heat dissipation. 



