author's abstract op this paper issuhh 

 by the bidlioqraphic service, november 17 



FURTHER STUDIES ON THE CHEMICAL COMPOSI- 

 TION OF THE BRAIN OF NORMAL AND 

 ATAXIC PIGEONS 



MATHILDE L. KOCH and OSCAR RIDDLE 



The Psychiatric Institute of the New York State Hospitals, and the Sta'ion for 

 Experimental Evolution, Carnegie Institution of Washington 



In an earlier paper ('18) we published the results of five analy- 

 ses made on the brains of normal and ataxic 1 pigeons. Two of 

 these analyses were of younger and older normal brains; three 

 were of brains affected to three different degrees with an heredi- 

 tary (Riddle, '18) lack of control of the voluntary movements. 

 Previous observation of the functional derangement led to the 

 conclusion that the seat of the disturbance was probably in the 

 brain. 



The five analyses just mentioned supplied some evidence that 

 the functional disorder is associated with deviations from the 

 normal composition of the brain. These deviations or differences 

 we interpreted as indicating a tendency toward infantilism or 

 chemical under-differentiation of the brain of the affected indi- 

 viduals. In other words, the brains of affected individuals of a 

 given age seem chemically more like the brains of normal indi- 

 viduals of a younger age. In that study the number of analyses 

 was not large and the brain (five brains in each analysis) was 

 analyzed entire — without a separation of its parts. 



In the present study ten additional analyses were made of 

 brain tissue obtained from birds of still other ages than those 

 previously used. Eight of these analyses were upon samples rep- 

 resenting separate portions of the brain — the cerebrum having 



1 In earlier papers the disorder was provisionally ca'Ied 'ataxia (?).' In view 

 of the work of Hoshino ('19), mentioned at the conclusion of this paper, and our 

 own present results, it is now perhaps unnecessary to qualify this description of 

 the disease. 



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