02 Investigation* on the Life-History 



stream ; yet the two fish from the upper reaches contained an identical 

 small liquefying organism, and the Bacillus coli oonvmunis, neither of 

 which was grown from the third fish from the river mouth. 



The two main factors which influence the number and nature of the 

 bacteria in the alimentary tract of the salmon when in tidal waters 

 preparing to ascend fresh-water streams, or during this ascent, appear 

 to be, 1 , the season of the year, including of course in this the influence 

 of the temperature of the water, and, 2, the number and nature of the 

 organisms present in the water. To suggest that organisms swallowed 

 with food can cause an increased tendency to early decomposition 

 appeal's to be not in accordance with the fact that the gastric juice of 

 fish when feeding contains much more acid than is required to destroy 

 or inhibit all organisms, especially those putrefactive forms which are 

 easily effected by the agent. When fasting the acidity is not sufficient 

 to kill the organisms which enter with the water swallowed ; when 

 feeding, many of the organisms fail to survive the action of the acid in 

 the secretion of the gastric glands. Tidal water must, contain fewer 

 organisms capable of living in the alimentary tract than fresh water. 



