38 VETERINAEY HYGIENE 



branches of industry in which animal or vegetable or mineral 

 substances are dealt with ; (vi.) branches of industry in 

 which mixed substances are manipulated. 



It is rather a satire on veterinary hygiene to find the 

 keeping of animals classified as an ' offensive trade.' 



It is to be feared that Dr. Ballard was well within the 

 truth in his classification, though the object of the veteri- 

 nary profession has been to prove that there is no necessity 

 for the keeping of animals to be offensive, if the elementary 

 laws of health are obeyed. Still in justice to the lower 

 animals, which have no voice in the matter, it would be 

 equally fair and truthful to classify the common lodging- 

 house as an ' offensive trade,' and a far more serious one to 

 the human community. 



In Dr. Ballard's second group there is every room for 

 improvement ; the business of butcher and knacker may 

 be offensive, particularly the latter, owing to the boiling 

 operations in dealing with the bone, flesh, and fat, and the 

 collection of putrefactive material on the premises. This and 

 allied matters will receive special attention in a later chapter. 



The third group comprises the trades in blood drying 

 and boiling, soap and bone boiling, tallow-melting, glue- 

 making, gut-scraping, and the business of the fellmonger 

 and tanner, and are justly described as ' offensive trades.' 

 The effluvium from these is very penetrating and sickly, 

 but there is no evidence that beyond the injury to one's 

 senses any harm results. It is equally clear that unplea- 

 sant as these trade operations sound, the nuisance resulting 

 from them would be insignificant if proper cleanliness and 

 destruction of noxious vapours were observed. 



The fourth group consists of certain processes whereby 

 vegetable material is manipulated, viz., the distillation of 

 wood, manufacture of oxalic acid from sawdust, and dis- 

 tillation of vegetable oils, etc. In the fifth group is cement- 

 making, brick-burning, gas manufacture, while the sixth 

 group comprises the effluvium from chemical ^works, dis- 

 posal of town refuse and manure-making. All these pro- 

 cesses are offensive but not necessarily harmful to health. 



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