In 1872 Cohn of Breslau announced that " putrefaction 

 begins as soon as Bacteria, even in the smallest numbers, 

 are introduced. It progresses in direct proportion to the 

 multiplication of Bacteria. It is retarded when the Bacteria 

 (for example by a low temperature) develop a small 

 amount of vitality, and is brought to an end by all influences 

 which either stop the development of Bacteria or "kill 

 them." 



Having now set forth the generally accepted theory of 

 the putrefactive process, and glanced at the successive 

 steps of the different investigators that have led up to 

 this belief, we may pass on to the subject-matter of this 

 paper, viz. : — 



Preservation by Conditions of Temperature. 



" Putrefaction," says Cohn, " begins as soon as Bacteria, 

 even in the smallest numbers, are introduced, and progresses 

 in direct proportion to their multiplication," and it follows 

 as a logical sequence that the different conditions between 

 sound fish and rotten ones are but the different stages in 

 the process of putrefaction. 



Preservation, in the sense here used, at any temperature 

 above 32° Fahrenheit, only retards this process ; below 32° it 

 suspends it ; but in neither case can it restore a condition 

 once lost. It is well known that freezing completely checks 

 all putrefactive action, and when in this frozen condition 

 meat or fish can be kept for an indefinite length of time. 

 A noticeable instance of this was seen in the salmon brought 

 from Labrador, in the s.s. Diana in 188 1. A part of this 

 cargo was taken from London to Australia, and after this 

 long voyage across the tropics and 200 days out of water, 

 these salmon were found to be in good condition. 



