of the Fishery Board for Scotland. 



31 



During the past few years this enquiry has been extended to the lower 

 sub-kingdoms — birds, amphibians, and fishes — and of these, fishes have 

 probably received the most consideration on account of their extensive 

 and valuable use as a foodstuff, and because they are the inhabitants of 

 waters from which water supplies are derived. 



Houston, in his report to the Royal Commission on Sewage Disposal, 

 with special reference to the contamination of shell fish, states, as regards 

 oysters, and in a later report (1903-04) on the bacteriological examina- 

 tion of the excreta of fish — both oysters and fish derived from deep-sea 

 water remote from sewage pollution — that typical bacillus coli, or even 

 atypical bacillus coli, are seldom detectable in the former, and are absent, 

 or only present in small numbers, in the intestines of fish. 



At the same time, the Commissioners had to regret the paucity of our 

 knowledge as to the distribution of the bacillus coli in nature. 



Recently Eyre, MacConkey, and Johnson have done a considerable 

 amount of work in this direction. Their results differ from those of 

 Houston in this respect, that they find the bacillus coli almost universally 

 present in the intestinal canal of fish. 



During the past nine months, in the intervals of other work, and as 

 opportunity afforded, I have examined the intestinal contents obtained 

 from a large number of different kinds of fish with the view of ascertain- 

 ing the extent of the distribution of the bacillus coli in fish. 



The media used : — 



( (a) MacConkey's bile-salt glucose peptone litmus solu- 

 tion. 



General media<( (b) Digralski and Conradi's nutrose litmus agar, and, to 

 1p,ss extent, neutral-red bile-salt agar and lactose 

 { litmus agar. 



(a) MacConkey's bile-salt glucose peptone litmus solution. 



Sodium taurocholate, - 5 grams. 



Glucose, ... 5 grams. 



Peptone, 20 grams. 



Water, - - - 1000 c.c. 



The constituents are heated until dissolved, then filtered and sufficient 

 neutral litmus solution added. The medium is then distributed into 

 Durham's fermentation tubes and sterilised by steaming for 20 minutes 

 for three successive days. 



(b) Conradi- Digralski agar medium. 

 This medium is rather tedious to prepare. 



(1) Agar Preparation. — To 3 lbs. finely minced horse flesh or minced 

 ox beef, add 2 litres of water, and let stand for 24 hours. Then boil one 

 hour and filter. To filtrate, add peptone sicca and nutrose, 20 grams of 

 each, and 10 grams sodium chloride. Boil one hour and filter. Then 

 add 70 grams bar agar, boil for three hours in koch or one hour in auto 

 clave, render slightly alkaline (using litmus paper), filter, boil for half 

 an hour. 



(2) Litmus Solution. — Kubel and Tiemann's, got from Grubler, 

 Leipsig, is the best. Take 260 c.c, boil for ten minutes, then add 30 

 grams pure milk-sugar and boil 15 minutes. 



