ideas were entertained as to the nature of the diseases which seemed destined to be the scourges of mankind, efforts were made to stamp them out. As might be expected, many of these efforts were of the rudest description, but the earliest of them aimed at the object which the most modern science also seeks to achieve, viz., the destruction of the contagious material. The term "disinfection" first occurred in literature toward the end of the last century. A French writer, Morveau, in 1801, published a work on "The Disinfection of the Air," but the word was used somewhat earlier by a few English writers.
The most ancient method consisted in destroying by fire everything that had been in contact with the source of infection, the idea, no doubt, being that as fire consumes what is visible, it likewise destroys what is invisible. It is possible that the practice of burning the dead was in a measure based upon the conviction that a source of danger to the living was thus got rid of. The thirteenth chapter of Leviticus contains the most minute directions for disinfecting cases of leprosy; destruction of suspected articles by means of fire, the copious use of water, and isolation of the leper, are the means prescribed. Inspection by the priest was to decide as to the efficacy of these measures. Among the Egyptians and certain Asiatic peoples, the fumigations used by the priests in exorcising disease were probably neither more nor less efficacious than similar processes in vogue at the present day in some European countries.
In the growth of ideas with regard to the causes of infectious diseases, the theory gradually took shape that the infecting matters were formed as a result of the processes of decomposition, and as these processes are generally attended with the development of more or less unpleasant odors, it seemed only natural to assume that the causes of the latter were also the causes of disease. Instead of regarding foul emanations as generally mischievous, the idea was entertained that there was something quite specific about them, and accordingly we find that attempts to mask or neutralize them were regarded as the best methods of checking the spread of infectious diseases. Deodorization came to be considered as equivalent to disinfection. The idea was the more welcome inasmuch as it could be carried into effect without destroying property and without much difficulty. The attempt was certainly in the right direction, for the destruction of noxious agencies was the object in view. Unfortunately, the means employed absolutely failed to effect their purpose, and belief in their efficacy caused very mischievous results, viz., a sense of false security and neglect of ventilation and cleanliness as regards sick persons and surrounding objects. In fact, the confident adoption of deodorants as a means of checking the spread of infectious diseases was a decidedly retrograde step as compared with the use of fire for destruction and of water as a purifying agent.
Chlorine gas was the deodorant which came into very general use
