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Vlll. — On Disinfectants: heing tlie substance of a Lecture delivered 

 in Decemher, 1865, nntJi a Report of further Experiments, Sfc. 

 By De. a. Voelcker. 



Contagion or infection signifies tlie communication of disease by 

 actual contact with sick animals, by contact with normal discharge or 

 abnormal secretions, or by means of effluvia arising from their bodies, 

 or by all articles which have been iu contact with diseased animals or 

 their discharges. 



This power to communicate certain diseases api^cars to reside in 

 extremely subtle substances, which under favourable conditions 

 develop and reproduce themselves in healthy animals with which 

 they come into contact. Hence the danger that infected animals and 

 all materials touched by them may spread the Cattle Plague. 



Our present knowledge of the structural and chemical properties of 

 infectious poisons is so scanty, and the difficulties attending investi- 

 gations into the natui'e of these subtle and unstable bodies are so 

 great, that we must not be surprised if the opinions of scientific men 

 respecting the nature of Cattle Plague j^oison arc greatly divided. 

 That we have to deal with a material though extremely subtle poison, 

 is, if I am not mistaken, generally admitted, not so the form and 

 precise nature of the i)oison. Although a good many microscopical 

 and physiological researches on this subject have been undertaken in 

 this country since the outbreak of the plague, the results obtained are 

 not sufficiently numerous and precise to warrant their publication in 

 detail. Whilst investigations of that kind are still actively j)ursued, 

 and men best informed on the subject hesitate to give a decided 

 opinion on the structure or the functions of the Cattle Plague poison, 

 it would not be right for me to mention names in connection with 

 any facts, or supposed facts, which the microscope may or may not 

 have brought to light. 



Without offering an opinion on the correctness of the observations, 

 I may state that careful microscopic observers have noticed, more 

 especially in the faeces of cattle attacked by the j^lague, very minute 

 and peculiarly organised cells filled with numerous spherical bodies, 

 moving to and fro with great activity. These cells and their animated 

 globular contents are extremely small, so that the highest power of the 

 most powerful microscope is necessary for witnessing their existence. 

 According, then, to certain competent authorities, that which pro- 

 duces the Cattle Plague is exceedingly subtle organic matter dis- 

 posed in organic cells, and only revealed by microscopic research. 

 This poison in more than one respect resembles in general character 

 ordinary vaccine virus. It may be dormant three or four days before 

 its peculiar vitalised cells with their contents become active. 



It is not the part of the chemist to say how the j^lague was j)roduced, 

 or what are the remedies to be api^lied in order to effect a cure. 

 I have no intention to trespass on the legitimate province of the 

 veterinarian, but I have felt it incumbent upon mo to direct special 



