224 MILK 



of 1 : 5000 there is a rapid decline of bacteria- for four to six hours, 

 a continued slow reduction up to twenty-four hours, and after that 

 multiplication begins. When formaldehyd is present in a dilution 

 of 1 : 10,000 to 1 : 20,000 there is evident a marked restraining in- 

 fluence which in a dilution of 1 : 40,000 is less distinct. The au- 

 thors think that 1 part formaldehyd in 40,000 parts of milk, as 

 advised by von Behring, improves the sanitary quality of the 

 milk if it is kept at 60° to 70° F. by preventing objectionable fer- 

 mentations. They further state that there is no reason to beheve 

 that in this proportion any marked injury could result to the per- 

 son consuming it. 



Whether formaldehyd is injurious to the health of the con- 

 sumer is a question that cannot be satisfactorily answered, and 

 which is largely dependent upon the quantity consumed and the 

 period for which its consumption is continued. Exact experi- 

 ments are difficult to conduct, and the experiments actually made 

 by a number of investigators were those with animals. Such 

 results as were obtained are not necessarily appHcable to hiunan 

 beings. However, some observations on the effect of this pre- 

 servative upon children are available. It should be further taken 

 into account that in some experiments formaldehyd and other 

 preservatives have been made with unnecessarily large amounts 

 of these substances. Formaldehyd in a concentration of 1 : 20,- 

 000 preserves the milk for several days, and it has never been 

 shown that this amount is actually injurious. Von Behring even 

 advocated the use of formaldehyd in a concentration of 1 : 40,000 

 in milk destined for infant feeding. 



On the other hand, it should be remembered that, as previously 

 stated, a preservative may be present in excessive quantity, either 

 through ignorance or repeated addition. Under such conditions 

 it is conceivable that the effect of formaldehyd on casein — that is, 

 rendering it less digestible — is appreciable and that the irritating 

 effect in the digestive tract is not negligible. 



Furthermore, it does not seem unjustifiable to assume that, 

 while occasional consumption of a small amount of formaldehyd 

 may be without untoward effect, the habitual ingestion of even 

 small amounts may be detrimental. It is well known that for- 

 maldehyd has an inhibiting influence on the digestive enzyms and 

 on enzyms in general if the concentration is 1 : 500 or greater. 



In regard to borax and boric acid, the same holds good as for 

 formaldehyd. Borax and boric acid in relatively large quantity 

 (1 to 2 per cent.) seem to produce a slightly deleterious effect on 

 the digestive system, but in smaller amount the question still 

 awaits solution. Indeed, it should be remembered that borax 

 and boric acid are easily eliminated through the urinary tract, 



