98 Comparative Power of some Disinfectant. 



Both caused the solution to become milky, though earlier by 

 12 hours with that exposed for only 5 minutes. 



63.) Two pieces for 3 and 10 minutes in a close-fitting box, 

 the vapour being more copiously evolved. The 3 minutes 

 piece became opaque in 60 hours, whilst the 10 minutes one 

 remained quite transparent. 



It follows from the whole series that whilst it is possible 

 to destroy the dried microzymes by an exposure to sulphur 

 fumes for 10 minutes, it can only be done under very favour- 

 able conditions. An exposure for 15 minutes, if at aU 

 thorough, will usually be sufiicient. 



III. — Experiments with Ozonic Ether. 



These were carried on in a bottle in the same manner as 

 with carbolic acid, about half a dram of the ether being put 

 into the bottom of a wide-mouthed bottle of about 5-oz. 

 capacity, the pieces of paper being suspended from a hook 

 on the under side of the cork. 



(1.) One piece each exposed to the vapour of ozonic ether 

 for 10, 30, and 60 minutes. The 10 minutes piece caused 

 opalescence in 4J days, the same time as the bacterialised 

 paper. The other pieces left the solution unaffected. 



(2.) One piece each for 10, 15, and 20 minutes. The 10 

 minutes piece caused only a slight opalescence after 5 J days, 

 the other pieces remaining transparent. 



It is clear from these experiments that in ozonic ether we 

 have a powerful disinfecting agent, from 10 to 15 minutes 

 of full exposure being sufiicient to destroy the dried micro- 

 zymes, and presumably the specific contagia of zymotic 

 diseases. It is true that the high price of the ozonic ether 

 would preclude its free use on ordinary occasions. These 

 experiments are the only ones with which I am acquainted, 

 as carried out in an exact scientific manner, and they have 

 considerable interest in their bearing on the external appli- 

 cation of ozonic ether in the form of ointment, as recom- 

 mended by Dr. Day, of Geelong, for the purpose of destroying 

 the contagium, and thus checking the spread of scarlet fever. 

 It is very possible that direct contact with any contagious 

 particles will render them powerless ; but in view of the 

 time required with the most concentrated vapour attainable, 

 it is scarcely possible that the amount escaping into the air 

 in the course of the process of inunction can have any effect 

 on dried particles of contagium, which may chance to be 



