I50 HODGE. [Vol. VII. 



I watched them flying at evening, " They don't seem tired 

 one bit." 



From results of experiments upon birds, with the great 

 amount of matter lost from the nervous system during a day's 

 work, I feel confident in chancing the prediction that a small, 

 active bird, an English sparrow, for example, could not be kept 

 awake and fluttering a single night without fatal results. I had 

 hoped, instead of the prediction, to have been able to report an 

 experiment of this sort ; but time and the opportunity have not 

 been conjoined thus far. 



In addition to signs of fatigue present everywhere in the 

 parts examined, the brains of these swallows held in waiting an 

 agreeable surprise. By reference to the table (X, Exp. VI), it 

 will be noticed that the cerebellum shows the highest per cent 

 of loss, nearly ten per cent more than the occipital cortex. The 

 same thing is true of the pigeon, but not of the sparrows. 

 Extreme cases naturally make a much stronger impression than 

 mean cases of nearly the same magnitude ; and such an extreme 

 case has been shown in Fig. 12 (PI. VIII), taken from the 

 cerebellum of the night swallow. It is to be compared with 

 Fig. 13, drawn from the morning bird. Cells could easily have 

 been selected for measurement which would have shown a much 

 greater percentage of loss; but, this not being allowable, the 

 figures in the table give presumably a fair average, while Figs. 

 12 and 13 present the extremes. From the figures, too, the 

 nuclei of Deiter's cells are seen to have shrunken, as well as 

 those of Purkinje. To the cerebellum is generally ascribed the 

 work of muscular co-ordination, and where could be sought an 

 instance of more delicate manipulation of muscles than must be 

 required to drive the wing of a swallow as it flits and whirls and 

 balances and wheels and darts, the whole day long } In the 

 pigeon and sparrows, although the nuclei of the Purkinje cells 

 show great shrinkage, these extreme cases are not met with. 

 These birds use their legs as well as wings. 



To discuss a result of this kind, however, carries us far ahead 

 of our present purpose and knowledge. It is exactly what 

 might have been expected, had the idea occurred ; yet, now 

 that it stands before us, we are afraid to believe it ; and will 

 promise not to, until further experiment is made. But the time 

 may come when we shall be able to study some phases of local- 



