30 Investigations on the Life-History 



only 0-0209 per cent. In the first two the proportion between the 

 umount of albumin digested and the acidity of the extract is exactly the 

 same. The acidity per cent, is 1-45 per cent, of the amount of albumin 

 acted on. 



It would thus seem that the amount of active ferment extracted 

 from the gastric mucous membrane appears to be exactly proportional 

 to the acidity of the extract in the salmon examined in this research. 



Table V. shows the figures relating to the peptic power and acidity 

 of the stomach extracts arranged as to season : 



TABLE V. 



FIGURES RELATING TO THE DIGESTIVE POWER AND THE ACIDITY. 

 ARRANGED AS TO SEASONS. 



Season. 



Dig^STKwer. ! Average Acidity. 



March, ; 9 14-;") Q-:>;-,:\ 



May and June, ; 10 13'1 0'07 



July and August, 6 O'O O'OOS 



September to December, 7 13'17 O'lH 



The result is very striking. The fish examined in March give a 

 comparatively high digestive power with the highest acidity, those 

 captured in Miay-June and September-December present a lower 

 digestive power, identical in amount in both periods, though the 

 acidity present in the fish of the latter period is almost three times 

 that of those in former. The fish caught in July and August have m> 

 digestive power and a very low acidity. 



(c) Relation of Peptic Activity to the Micro- Orya nisms present. 



Table VI. is formed of figures relating to the fish in which both the 

 digestive power of the stomach mucous membrane and the number of 

 bacteria present were investigated. The bacteriological data will be 

 considered more fully later on, but a direct comparison between the 

 results of the two investigations is useful in this place : 



[TABLE. 



