n6 Epidemic Diseases. 



known by their fatal consequences. If you want to kill 

 any organism, from the highest to the lowest, put it into 

 a fire or furnace. The organism is completely taken up and 

 reduced to gases and vapour, and every spark of life is extin- 

 guished. The liquid mode of disinfection consists in sur- 

 rounding the infected matter with some liquid containing any 

 substance in solution which has the property of killing an 

 organic body. He illustrated this by stating that all the fisher- 

 men in a district, with their rods, nets, and lines, cannot 

 destroy all the fish in any particular lake ; but if the contents 

 of some flax dam be emptied into the lake, all the fish, young 

 and old, large and small, will soon be dead, killed or poisoned 

 by the action of the flax- water. The aerial mode of disinfection 

 consists in surrounding and filling the pores of the infected 

 matter with a sufficient volume of gases or vapours which have 

 the property of killing all the disease organisms contained in 

 the infected body or mass of matter. It is impossible to 

 over-estimate the extraordinary effect that even slight changes 

 in the aerial surroundings or environments have upon every 

 organism, from a man down to the disease-producer. The 

 lecturer then proceeded to explain the properties of the different 

 liquids and gases commonly used for disinfecting purposes, 

 referring especially to carbolic acid, whose characteristic pro- 

 perty is its extraordinary power of destroying the lowest 

 forms of life. Carbolic acid vapour can be generated by 

 pouring the liquid acid into a hollow tin heater which has 

 been raised to a very high temperature in any ordinary fire, 

 and large quantities of that vapour can be thus thrown off in 

 a very short time. In fact, there is no practical difficulty in 

 generating any quantity of that vapour in any place where 

 there is sufficient fire to heat up the little machine to which 

 he referred. That vapour does not attack the metals, and 

 does not destroy articles exposed to it ; and when moderate 

 quantities of it are used it has no injurious action on the 

 human or animal system, being thus unlike all the other dis- 

 infectants of that class. After many years' experience in small- 

 pox, typhus fever, scarlatina, and diphtheria, he can with 



