THE PRESERVATION OF MILK 63 
to the gallon would have considerable effect, and experiments to test tliis are in progress. Tlie 
results, I think, of these experiments cannot fail to lead us to infer that similar if not more injurious 
effects would be produced by repeated administration of similarly 'preserved' milk as the daily food 
of young infants, and all the evidence tends to prove tliat milk, especially during the summer 
months, is habitually and systematically 'doctored.' 
The Use of Formalin 
Formalin has only been introduced commercially within the last two or three vears. 
It has been but little used in medicine except as a diluted vapour in the treatment of phthisis 
and whooping-cough, and no exact dosage has been assigned to it. Formol, formal, and 
formalin are terms in use for the commercial liquid which contains about 40 per cent, of pure 
formaldehyde (CHOH). The extent of its use as a milk preservative is seen from Dr. Hill's 
figures. Dr. Hill found formalin in 47 out of 1,000 samples of milk examined. In some 
American cities its use had become so extensive that the sanitary authorities* provided each milk 
inspector with a small chemical outfit, consisting of ferric chloride solution, sulpliuric acid, pipettes, 
and test-tubes, in order to test for formalin. After the passing of an act in 1895 prohibiting tlie 
addition of any preservative to milk the open use of formalin ceased, but substitutes were presented 
for patronage under various names, such as ' freezine,' ' milk sweet,' ' callerine,' &c., which were 
found to be preparations of formalin. Costly circulars, booklets, and pamphlets were largely 
distributed to milkmen extolling the merits of the various preparations. The use of these was 
often described as ' a new process for keeping milk and cream sweet without ice.'' The user was 
assured by the circulars that 'it cannot be detected when used — in fact, a chemist could not find 
any trace of it if the milk were analyzed.' The medical officer of health of Philadelphia describes 
its use 'as wholly mercenary, regardless of the injurious effects upon the digestion, especially of 
children and invalids.' CASSALt gives his opinion that ' formic aldehyde is a substance which 
must be regarded as even more objectionable than boric acid.' 
Action of Formaldehyde on Digestive Ferments 
RiDEAL and Foulerton extended their experiments also to the action of formalin with the 
following abstracted results : — 
A. — Amylolytic Digestion 
1. — Salivary Digestion of Starch. 
Strength of formalin. 
Retarding efFect. 
I in 100,000 
I „ 50,000 
I „ 10,000 
0.2 per cent. 
+•0 
11.0 ,, 
* Annual Report of the Bureau of Health, Philadelphia, 1898. f ' Public Health,' 1899, p. 535. 
