462 Agricultural Experiment Station, Ithaca, N. Y. 



and preserving agent. It is sold as a 40 per cent, solution and 

 quoted at |.G0 per pound. 



There is no doubt that formalin is a most effective preserving 

 agent. Prof. R. T. Thomson {Analyst, xxi, p. 65) shows that it 

 is more effective than boracic acid, borax, salicylic or benzoic 

 acids. According to his experiments 17^ grains per gallon kept 

 milk sweet 11 days. 



The 40 per cent, solution of formalin has a specific gravity of 

 1.080. Since a gallon of water weighs about 8 1-3 lbs. a gallon 

 of the formalin weighs 8 1-3 times 1.080, or 9 lbs. At |.60 per lb. 

 a gallon of this 40 per cent, solution costs $5.40. From one gal- 

 lon of the 40 per cent, solution 5 5-7 gallons of a 7 per cent, solu- 

 tion can be made. Therefore the difference in cost between for- 

 malin bought as such and callerine at |6 per gallon is: 



1 gal. formalin |5 . 40 



5 5-7 gal, callerine at |6 per gal 34 . 28 



If bought in the Special Working Sample (16 oz.) at |1.25 the 

 difference in cost is: 



1 lb. formalin | . 60 



5 5-7 lbs. callerine at |1.25 7.14 



Or in other words $34.28 and |7.14 are asked, respectively, for 

 $5.40 and $.60 worth of formalin. By i)urchasing the original 

 material at $.60 per lb. and adding water at the rate of 4 4-7 lbs. 

 to each pound of formalin a solution of the same strength as 

 callerine is obtained. 



As to the effects of formalin on digestion Prof. R. T. Thomson 

 in the article above referred to quotes from Dr. Leffmann " Pro- 

 cesses of digestion are allied to processes of decomposition, in so 

 far that the latter are frequently preceded by transformation 

 under the influence of ferments. We may infer then that what- 

 ever prevents putrefaction at least delays digestion." While 

 there is no evidence that evil effects have followed from the use 

 of such small quantities of formalin as are necessary to preserve 

 milk, it seems advisable from Dr. Leffmann's statement to be 

 cautious about its use in any considerable quantity. 



