320 



THE GROWTH OK THE BRAIN. 



of exercise. Hodge was thus able to demonstrate 

 fatigued cells in the spinal 

 ganglia of English sparrows ; 

 in the large cells from the 

 cerebellum of the swallow ; in 

 cells from the cortex of the 

 pigeon and those from the 

 antennary lobes of the honey- 

 bee, the animals being taken 

 at the end of the active day ; 

 whereas in animals taken in 

 the morning the cells in these 

 localities had the characters 

 of those at rest. 1 



Since these first experiments 

 this same author has been able 

 to put two sympathetic ganglia 

 under the microscope, and to 

 stimulate one while leaving 

 the other at rest, and thus to 

 watch and compare in the 

 living cell the changes occur- 

 ring during stimulation. In the 

 control specimen no change 

 took place in the cells during 

 the experiment, while in the 

 former, progressive changes 

 occurred, of which Fig. 75 is 

 a representation. This series of 

 experiments presents the first 

 good anatomical alteration to 

 be correlated with the loss of 

 power following exertion ; and 

 though thus far they have only casually been applied 

 ' Hodge, Journ. of Morphology -, 1894. 



