No. 2.] CHANGES m NERVE CELLS. I 51 



ization in the brain by means of changes in the cells due to 



fatigue. 



The pigeons were not introduced solely to add variety to the 

 list of animals used ; but with a distinct purpose of another 

 kind. Arrangements had been made with a pigeon fancier 1 of 

 Worcester, to furnish a number of trained homing pigeons. 

 These birds, if taken away from their loft and liberated, are 

 said to fly without alighting during the first day, or until the 

 loft is regained. Records have been scored of over five hundred 

 miles, air-line distance, on the day of liberation {j-j, p. 366), 

 the birds coming to loft, I am told, too fatigued to hold up their 

 wings from the floor. It was intended to make at least one 

 experiment with them to show extreme fatigue, fatigue from 

 which, I am informed, pigeons require not only a night's sleep, 

 but several days' time, to fully recover. The birds were lost in 

 course of training, and I was obliged to leave Worcester before 

 others could be obtained.^ I had intended using the common 

 pigeons as normals, to show the effect of a moderate day's work, 

 for the homing pigeons, which, it was hoped, would demonstrate, 

 by comparison, extreme fatigue. 



Failing of the homing pigeons was possibly for the present 

 a piece of good fortune, for I bethought myself of another ani- 

 mal, the proverbially "busy bee." From these, at any rate, I 

 have obtained most striking results. They may be seen at a 

 glance by comparing Fig. 10 (evening) with Fig. 11 (morn- 



On the morning of June 10, after securing my swallow, I 

 stationed myself by a patch of raspberry bushes in full bloom 

 and within a stone's throw of a small apiary, and watched for 

 the bees to come. At six o'clock sharp they came. The first 



1 The writer refers to Mr. Frank Keith, to whom he is under great obligations for 

 kind assistance and valuable information regarding the use of homing pigeons. 



2 Homing pigeons are expensive, when well bred, costing, minimum price, six 

 dollars per pair, for young birds. Their training may cost an indefinite amount 

 more. I have, however, to thank Dr. S. Weir Mitchell for a fine loft of about 

 thirty blooded homing pigeons; a number of which are being trained at this 

 writing for longest possible flights in order to furnish material for the above- 

 mentioned experiments. It is. however, a much longer undertaking than I antici- 

 pated. The birds attain full maturity in not less than four years. Young pigeons 

 lack the mental development, the grit, and perseverance, to put forth the great amount 

 of effort desired. But the experiments will be reported in due time. 



