i86 FERMENTATION IN MILK 



Cows. — It is important that after the occurrence of any taint 

 in the milk, the cows should also be specially cleaned. The 

 udders should be washed with water and soda solution (2 per 

 cent.) or boracic acid solution (3-5 per cent). 



The most convenient and economical methods of producing 

 formaldehyde gas, which is probably the best gaseous disinfectant 

 to use, are as follows : — 



(i.) By the vaporising of polymerised formic aldehyde in the 

 form of paraform tablets placed in an old iron kettle or other 

 utensil suspended over a lamp, or in the Alformant lamp A of the 

 Formalin Hygienic Company. 



The paraform is supplied in tablets of i gramme, the vapor- 

 isation of ten tablets being sufficient for the disinfection of 1000 

 cubic feet of ordinary space. 



• Taking the average dairy at, say, a cubic content of 2000 feet, 

 this would mean the expenditure of twenty tablets, the expense 

 of which is trifling. Should, however, there be any difficulty in 

 making the dairy comparatively air-tight, some margin over the 

 quantity should be allowed, to make good any escape of the gas 

 through unenclosed apertures. After carrying out the measures 

 above recommended, the tablets should be placed in the receptacle, 

 the lamp lit, and the door closed from without and made as air- 

 tight as possible. Six hours may be taken as the minimum of 

 time required for thorough disinfection, but a more convenient 

 course will be for the door to be kept closed till the following 

 morning, when the utensils can be taken out, and the dairy put 

 in order for the work of the day. 



(ii.) Autoclave under pressure. — Trillat's apparatus for the libera- 

 tion of the aldehyde from formalin (a 40 per cent, solution of formic 

 aldehyde being used, to which is added a little calcium chloride) 

 is equally efficacious, but the expense of the autoclave is a serious 

 consideration. 



(iii.) Retort without pressure may also be used. In both these 

 cases the gas is passed, by means of a tube, through the keyhole 

 or some other hole in the door, the apparatus remaining outside 

 the room. 



(iv.) Lmgner's apparatus has been used for stables and cow- 

 sheds with some success. It is a steam generator which vaporises 

 formalin.^ 



^ For particulars as to working disinfecting apparatus, etc., see A Practical 

 Guide to Disinfection, by M. J. Rosenau, M.D., and F. J. Allan, M.D., 1903, 

 pp. 93-118 ; and Supplement, pp. 33-53, and 59-70. 



