GENERAL CONDITIONS OF BRAIN- ACTIVITY. 101 



delicate siirface-tliermometers simultaneously against the 

 scalp, lie found that when different muscles of the body 

 were made to contract vigorously for ten minutes or more, 

 different regions of the scalp rose in temperature, that the 

 regions were well focalized, and that the rise of temjDerature 

 was often considerably over a Fahrenheit degree. As a re- 

 sult of his investigations he gives a diagram in which num- 

 bered regions represent the centres of highest temperature 

 for the various special movements which were investigated. 

 To a large extent they correspond to the centres for the 

 same movements assigned by Ferrier and others on other 

 grounds ; only they cover more of the skull.* 



Phosphorus and Thought. 



Chemical action must of course accompany brain-activity. 

 But little definite is known of its exact nature. Cholesterin 

 and creatin are both excrementitious products, and are 

 both found in the brain. The subject belongs to chemistry 

 rather than to psychology, and I only mention it here for 

 the sake of saying a word about a wide-spread j)opu- 

 lar error about brain-activity and phosphorus. ' Ohne 

 Phosphor, kein Gedanke,' was a noted war-cry of the 

 ' materialists ' during the excitement on that subject which 

 filled Germany in the '60s. The brain, like every other 

 organ of the body, contains phosphorus, and a score of 

 other chemicals besides. Why the phosphorus should be 

 picked out as its essence, no one knows. It would be 

 equally true to say ' Ohne Wasser kein Gedanke,' or ' Ohne 

 Kochsalz kein Gedanke ' ; for thought would stop as quickly 

 if the brain should dry up or lose its NaCl as if it lost its 

 phosphorus. In America the phosphorus-delusion has 

 twined itself round a saying quoted (rightly or Avrongly) 

 from Professor L. Agassiz, to the effect that fishermen are 

 more intelligent than farmers because they eat so much fish, 

 which contains so much phosphorus. All the facts maybe 

 doubted. 



The only straight way to ascertain the importance of 



* A "New Study of Cerebral Cortical Localization (N. Y., Putnam, 

 1880), pp. 48-53. 



