Fatigue of Excitation and Fatigue of Depression etc. 39 



venous injection of 3 cc. of lactic acid diluted to 50 cc. was made. 

 There "was no apparent ill effect. Killed after six hours. 



Experiment M.-E. 31. Elderly collie dog. Weight 19,57 kg. Under 

 ether, 350 cc. of a 5 °/ lactic acid in warm saline were given intravenously. 

 The total amount of full strength lactic was 17,5 cc. The animal was list- 

 less, apathetic, almost comatose and vomited. As usual, the respiratory 

 rate was initially increased. Killed after five and one half hours. 

 On the basis of three experiments, the lethal dose of mono-potas- 

 sium phosphate in cautious intravenous injection of a l°/ solution 

 was found to vary from 0,15 to 0,25 grams per kg of body weight. 

 Death in each case was due to respiratory failure, following a marked 

 initial excitation with subsequent spasmodic breathing. 



Experiment M.-E. 39. Old mongrel terrier bitch. Weight 5,58 kg. 

 Under ether, 55,8 cc of a 1 °/ solution of KH. 2 PO^ (0,1 gram per kg) 

 and 55,8 cc of a 5°/ Merck's sarcolactic acid (0,5 cc per kg, total 

 amount 2,79 cc) were administered together intravenously. There 

 was the usual marked symptomatic effect. Killed after six hours. 

 This concludes the experiments on the possibility of exciting the 

 changes of activity by fatigue products. Even in the more severe of 

 these depression changes are instead recognizable, The further experi- 

 ments of prolonged administration of sarcolactic acid and mono-potas- 

 sium phosphate, which resulted in frank depression, are more suitably 

 recorded elsewhere under that particular head (1913 b). Briefly, the 

 administration of these, both alone and in combination, was prolonged 

 on three rabbits for a period of five to ten days. 



The Analysis of the Experiments on the Relation of the Fatigue 

 Substances to Functional Activity. (Table 1.) 

 The basis of the analysis is the differential counting of cells as 

 set forth in Table 1 in summarized form. The advantages and defects 

 of the method have been previously discussed (1909 c). It is invaluable 

 in affording definite and concrete figures, although they are to a cer- 

 tain degree approximate, partly from technical difficulties, partly from 

 natural variations of localization. In no case, however, have selected 

 areas been chosen for the counting. Table 1 will be used to take' 



