30 



Part III. — Twenty-sixth Annual Beport 



bacteria always present, the bacteria coli is not infrequent, and is readily 

 detected in cultures, especially on the Conradi and Digralski media. 



In some cases these processes go on so rapidly that there may be com- 

 plete digestion of a part of the abdominal wall in 36 hours, or even less, 

 after death. In 48 to 72 hours it may occur in about one-half, and in 

 very few will the abdomiual wall remain intact after 96 hours. 



Undoubtedly, as rigor mortis passes off, this process of auto-digestion 

 in the gut and in the surface of the adjacent abdominal walls is early 

 accompanied by, and soon finally superseded b} r , putrefactive processes, 

 the presence of which is readily detected by : — 



(1) The softening and apple-jelly appearance of the abdominal walls. 



(2) The increasing stale odour, becoming offensive and finally putrid. 



(3) The reaction of the muscles, becoming alkaline to litmus paper. 



(4) Sometimes in ungutted fish the presence of hydrogen sulphide 



can be detected. 



At this stage bacteria are always present and can be detected either by 

 direct microscopic examination or very readily by making cultures from 

 the tissues. 



The above statement has reference chiefly to ungutted fish. The 

 removal of the gut immediately after capture, or at least soon after 

 capture, will to a considerable extent preclude the process of auto- 

 digestion. Consequently, the abdominal muscles remain longer firm, and 

 discoloration, with its accompanying softening and putrefaction, are 

 delayed. The micro-organisms present in cultures from the softening 

 abdominal muscles will also differ from those in ungutted fish, inasmuch 

 as the bacillus coli will usually be absent. 



Ungutted fish during the cold season may keep sufficiently fresh for 

 one or even three days, but if kept longer, whether iced or not iced, the 

 flesh becomes saturated with acrid ferments and exhibit a sour smell. 

 When such fish are cooked they are found to have lost much of their 

 natural flavour. If cured, it will be found that they have lost much of 

 their flavour, and that they do not keep well. 



15. The Distribution of the Bacillus Coli in Fish. 



For some time it has been well known that, in man, this bacillus is the 

 chief inhabitant of the small intestine, and also in the large intestine it 

 finds a habitat associated with many other micro-organisms. Recently, 

 with the development and more extensive application of sanitary and 

 bacteriological science — especially in the consideration of food and water 

 supplies — this bacillus has been studied more widely in nature, and has 

 now been proved to be present m the dejecta of most, if not of all, 

 mammals ; and that, with the exception of some slight difference in 

 culture, in pathogenicity, and as regards fermentaton of the different 

 sugars, there is no essential biological difference between the bacillus 

 coli found in man and in the lower mammals. 



It has frequently been attempted to formulate these differences as a 

 basis for differentiation and classification of the bacillus coli found in the 

 intestine of man and those found in lower animals, and to extend its 

 application to the consideration of sewage pollution, water supplies, etc. 

 But, however desirable this may be, in considering many public health 

 questions, in practice it fails, and at the present moment there is no 

 reliable means of distinguishing between bacillus coli derived from animal 

 excreta and those derived from human excreta. 



