774 THE POPULAR SCIENCE MONTHLY. 



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, Mor- 

 veau, 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 every- 

 thing that had been in contact with the source of infection, the idea, 

 no doubt, being that as fire consumes what is visible, it likewise de- 

 stroys 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. In- 

 spection by the priest was to decide as to the efficacy of these meas- 

 ures. Among the Egyptians and certain Asiatic peoples, the fumiga- 

 tions 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 dis- 

 eases, the theory gradually took shape that the infecting matters were 

 formed as a result of the processes of decomposition, and as these pro- 

 cesses 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. Deodori- 

 zation 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 at- 

 tempt 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 



