INDIVIDUAL HYGIENE 133 



impurities of all possible kinds. Wherever animals and plants exist 

 carbonic acid and various organic substances excreted from the system are 

 constantly being thrown into the air. Living organic bodies are also 

 continually being conveyed by the air, sometimes long distances, and in 

 this way certain infective particles are conveyed from diseased to healthy 

 animals. A large number of these, however, cannot in all probability be 

 carried to any great distance, unless under the influence of powerful 

 currents. It is recorded that ships, when several hundred miles from land, 

 sometimes have their sails and yards covered with sand; it can hardly be 

 questioned, however, that such heavy material could only be conveyed 

 such a distance by very high winds. 



Examination of air is only possible to the unprofessional observer by 

 the use of the organ of smell, and it may be said of air, as it has already 

 been said of water, that the presence of a smell of any kind is proof 

 of contamination. The taste and the eyesight will assist in certain cases 

 when the air becomes charged with the smoke emanating from chimneys 

 of factories in which trades, which are described as noxious trades, are 

 carried on; but for the purpose of detecting invisible suspended matters, 

 organic bodies, carbonic acid, watery vapour, ammonia, and other solid and 

 gaseous products, the knowledge and skill of the expert are absolutely 

 essential. 



INDIVIDUAL HYGIENE 



Under the above heading Dr. Parkes, in his classical work on Hygiene, 

 refers to individual hygiene as a large subject which would require a 

 volume to itself; it will be understood that by the use of the term that 

 great authority means to include everything which is in any way connected 

 witli the habits of the individual: — his work and his amusements, the 

 nature of his diet, and the amount of exercise and rest which he takes, 

 the kind of clothing which he wears, the climate which he inhabits, in 

 short, everything which the man does or leaves undone. Even the exercise 

 of his reasoning faculties, to quote the words of the author, " the amount 

 of mental w r ork, the practice of general good temper, cheerfulness, and 

 hope", are all concerned in digestive processes, and they are all included 

 in the term individual hygiene. Obviously in applying the term to the 

 lower animals a very large part of the subject, i.e. everything which relates 

 to mental processes and the exercise of volition, everything indeed which 

 the individual does by intention, must be necessarily omitted, because the 

 animal in domestication has no choice in the matter of his diet, the amount 

 of exercise or work, the gratification of his wants, whether reasonable or 

 otherwise, as everything is arranged by the stable attendants. For these 



