INTELLIGENCE 



work. (2) The voluntary muscles have a capillary supply 

 far less abundant than that of the fibers of the heart muscle. 

 If oxygen deficiency in the great mass of voluntary muscles 

 were the cause of the limitation of the size of the brain, then 

 the process of evolution would have supplied a larger 

 amount of blood to the great mass of voluntary muscles, 

 as in the case of the whale. 



If a fever due to an infection of any kind has reached a 

 temperature of approximately 108, heatstroke will develop. 

 There is no oxygen deficit in the muscles of such a patient, 

 since he is relaxed in bed. We took the temperature of the 

 winning horse at the end of a trotting race in July and 

 found it to be 104. It is clear enough that an oxygen deficit 

 may be coincident with the limitation of the speed of a 

 race horse. Considering the fact that even in a short race 

 the temperature of this horse rose to 104, it is more 

 probable that the oxygen deficit is a protection against 

 death from heatstroke. If in this horse there had been more 

 capillaries supplying more oxygen and nutrition to the 

 muscle, the oxidation in the muscles and hence the amount 

 of heat would have been increased, let us say, 4 further, 

 and this winning racing stallion would have died on the 

 track of heatstroke. 



It is significant that in the application of heat therapy 

 the temperature of the patient can be safely increased 

 only to 108. In such a case, when the source of heat is 

 removed, the temperature of the patient returns to the 

 original level. If the temperature is increased to 108.5 

 heat stroke occurs. 



The brain contains the greatest percentage of the most 

 sensitive of the nitro compounds. This fact explains why 

 the brain is the first point of the organism to succumb to 

 heatstroke. The first symptoms of heatstroke are mental 

 confusion and stupor, followed by coma; or the disintegra- 

 tion of the brain may be so abrupt as to be equivalent to 

 detonation. Thus the chemical picture is in accord with our 



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