256 Professor Sheridan Delepine [Feb. 13, 



connection with the pork pies. It seems, therefore, desirable that 

 infants should not be fed on such milk. 



The effects of refrigeration, during transit, upon the properties of 

 milk received in Manchester from various counties, offer a proof of 

 the dangers connected with this multiplication of bacteria in milk, and 

 also the that the danger is not without remedy. 



About 50 per 1000 guinea-pigs, inoculated with non-refrigerated 

 milk coming from a distance, died within ten days after inoculation. 

 Not more than 3 per 1000 died when inoculated with milk which had 

 been kept cold during transit. If the milk had been refrigerated 

 immediately after milking, no death at al 1 would have occurred, unless 

 the milk had been obtained from much-diseased cows. 



Preservation by means of Chemical Preservatives. 



Another source of danger, which I must mention before concluding, 

 is that which results from the addition of preservatives to perishable 

 food stuffs, such as meat, milk, cream, butter, etc. Dealers in those 

 articles are exposed to serious losses owing to putrefactive changes, 

 which occur more or less rapidly in such articles. In most cases 

 these putrefactive changes can easily be prevented by refrigeration ; 

 but in many cases that method is not economical or convenient, and 

 therefore chemical substances, such as salicylic acid, boracic acid, 

 formalin, which arrest putrefaction, are extensively used by various 

 trades. Some of these substances, when taken in sufficient quantities, 

 have been shown to be more or less detrimental to health ; and as a 

 matter of fairness to the consumer, it is obviously desirable that the 

 addition of such substances should be made known to the purchaser 

 who is not anxious to try upon himself experiments regarding the 

 action of drugs taken in small doses over an unlimited period of time. 

 It is not, however, to this aspect of the question that I wish to 

 attract attention specially. There is another aspect which is of 

 more importance. 



Some of the preservatives in common use, although tbey are able 

 to check the growth of putrefactive organisms, are unable to arrest 

 that of some of the disease-producing bacteria which may be present 

 in food ; and this is a serious source of danger. 



During my investigation of the Derby outbreak, I was struck 

 with the absence of putrefactive changes in the jelly of the pies, 

 and previous experiments led me to infer that a preservative had been 

 added to it in fairly large proportion. On analysis I found that the 

 preservative used had been boracic acid. 



If such a preservative had not been used the pies would rapidly 

 have become stale, and few of the stale pies would have been eaten. 

 Instead of this, the pies retained the appearance of freshness whilst 

 the deadly bacillus was multiplying in their midst. It will have 

 been noticed, that the pies which had been kept for some time had 

 proved more noxious than those which had been consumed at an 

 earlier date. 



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