36 REPORT — 186G. 



position, -whilst they act with intense energy on the inodorous germs of infection 

 which these gases may cany into the atmosphere along ■\\-ith them. 



If, therefore, the matter which conveys infection from one person to another be 

 of the nature of an organized germ, if its tremendous powers of destruction are 

 due to its vitality, then antiseptics are the only agents fitted to deal with these 

 special cases ; for whilst they leave almost untouched the majority of simply odorous 

 o-ases, they seek out and destroy the one thing to be feared. 



Now, of all antiseptics, those known as the tar acids, are the most powerful ; 

 and of these, commercial carbolic acid maybe regarded as the representative. The 

 powerful action which carbolic acid exerts on the phenomena of life, is the most 

 remarkable property ■\\-hich it possesses. It may be looked upon as the test proper 

 for distinguishing vital from purely physical phenomena ; and in most cases its 

 action is diaracterized by the certainty and dofiniteness of a chemical reagent. 

 In the presence of carbolic acid the development of embryonic life is wellnigh im- 

 possible ; and before its powerful influence all minute forms of animal existence 

 inevitably perish. The vapour of carbolic acid in the atmosphere exerts a specially 

 selective power on all minute organisms possessing life. If the iufectious matter 

 of cholera is possessed of organic vitality, as is now almost universally admitted, 

 it will be destroyed beyond the possibility of revival, when brought in contact 

 with this vapoiu'. 



Although the properties of carbolic acid are so valuable, the en-or I have already 

 alluded to must be avoided, of considering it applicable to every case where disin- 

 fection is reqm-ed. Whilst its peculiar properties render it of wide applicability, it 

 may on many occasions advantageoush' be replaced by other disinfectants. Thus, 

 for pmifying water for drinking or culinary purposes, it is far inferior to ebullition 

 in the presence of Condy's fluid, which acts in this respect perfectly. Again, the 

 liquid nature of carbolic acid renders it not so appropriate as McDougall's or Cal- 

 vert's powder for many purposes, an excess of liquid being frequently a disadvantage 

 where large quantities of solid offensive matter have to be dealt with, in which case 

 either of the powders above mentioned is more suitable than carbolic acid. 



Although much more expensive than carl)olic acid for equal amounts of puii- 

 fjang work, chloride of lime also is a more appropriate agent where mere deodori- 

 zation is the chief desideratum. 



It has been assumed, I think on insuflicient groimds, that the mere addition of 

 permanganate of potash to drinking-water -nail certainly destroy the cholera virus. 

 The oxidizing powers of this agent, although very energetic on dead organic matter, 

 are successfully resisted by living organisms. Animalcules will live without appa- 

 rent inconvenience for some time in water tinted with permanganate ; and, assuming 

 that the cholera poison possesses organic vitality, we liave no guarantee that_ the 

 ao-ent in question will eftect its destruction. For this reason, I should be inclined 

 to prefer boiling tlie water after adding permanganate. 



Let me here' state a fact which ought to be generally known in respect to car- 

 bolic acid. For disinfecting purposes, as ordinarily applied, it is very extravagant 

 to use it in the undiluted form. Except in special cases, the aqueous solution of 

 the acid should invariably be used. Water will dissolve about 4 per cent., and for 

 most purposes this solution is a better disinfectant than the undiluted acid. A 

 small insect which is killed in a few seconds by immersion in the 4 per cent, 

 aqueous) solution, will live for a minute or more when covered with the undiluted 

 acid. When the aqueous solution is added to sewage, the latter is at once disin- 

 fected ; but on adding to a similar quantity of liquid far more than the corre- 

 sponding amount of undiluted acid, this sinks, as a heavy oil, to the bottom, where 

 it remains ; and unless the mixture be well shaken, so as to bring the oil in con- 

 tact ^^•ith every portion, complete disinfection will not be efl'ected for some time. 

 To throw undiluted carbolic acid down the drains, as is done in many places at the 

 present time, is simply to throw money away. 



AUow me, in conclusion, to draw attention to the gTeat importance of the scientific 

 prosecution, by qualified persons, of accurate experiments and observations in 

 reference to the cholera, similar to those undertaken in respect to the Cattle Plague. 

 Tlie third report of the Cattle-Plague Commission has given us more insight into 

 that pestilence than we possess of any human zymotic disease ; and there is no 



