No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 209 



part, and with such rapidity that the effluent fluid is practically or 

 wholly innocuous and inoffensive but still valuable as a fertiliser 

 — See also note, page 253 infra. 



The plan, dimensions, method, etc., can be obtained from books 

 or from the Sanitary Engineer; a model which, mutatis /nntaiicfis, 

 could be followed, is the small system for disposing of sewage 

 (from the latrines, etc.) in use at the Imperial Research Institute, 

 Bangalore. 



In the case of the fish guano factories the use of lime, alum, 

 soda ash, etc., is in any case advisable before treatment in the 

 septic tanks, since such substances give to the fluid the alkalinity 

 which favours the action of the bacteria and thus hastens the 

 process ; chloride of lime, however, should not be used in such case 

 as it is inhibitive and even dec'ructive of bacteria. 



102. The due use, consistent with sanitary requirements, of 

 these waste waters is very desirable and should be kept in view, 

 and made the subject of careful and intelligent experiment. 



Stearine. 



103. This has been mentioned as regards menhaden oil stearine 

 in paragraph 39 supra. It is noteworthy that more stearine is 

 found in menhaden oil from the Southern coast of the United 

 States of America than in that from the Northern, and this is 

 paralleled by the large amount found in Madras sardine oils. The 

 general proportion has not been ascertained but has always been 

 estimated at from one-fourth to one-third of the whole oil, which 

 corresponds with the amount found in American oil. But it is to 

 be noted that oil decanted from the stearine which is perfectly 

 clear at Madras temperatures, deposits further amounts when taken, 

 say to London : exhibits of perfectly clear oil sent to the Imperial 

 Institute, Kensington, were very disappointing in appearance. 



Apparently the stearine is obtained in quantity because of the 

 high temperature (boiling) at which the oil is prepared; for when 

 fat fish are heavily salted and kept in masses in receptacles 

 (pilchardised) at ordinary temperatures, the oil which is skimmed 

 from the surface or expressed by pressure with screws in barrels, 

 is practically free from stearine, though of a rich, dark, brownish 

 red colour. This is also the case with pilchard oil in Cornwall 

 where this practice is in vogue and whence it was copied (see 

 Bulletin on Fish-curing); pilchard oil is, or was, considered in 



