PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 535 



After deciding to continue the discussion of this subject, the 

 Association adjourned. 



American Institute Polytechnic Association, 



October 25, 1866. 



Prof, S. D. Tillman in the chair; T. D. Stetson, Esq., Sec'y. 

 The chairman presented the following extracts from scientific 

 papers : 



Disinfection in Connection with the Cattle Plague. 

 Disinfection, in the sense in which it is used here, implies 

 the destruction of animal poison, in whatever way it is accom- 

 plished. To find a perfect disinfectant for the cattle plague poi- 

 son would be to stop the disease at once. We have naturally 

 been very desirous of discovering a substance with such a power; 

 but much more evidence is necessary before we can venture to 

 :affirm that success has been obtained. In the first instance we 

 requested Dr. Angus Smith to undertake this subject, with a view of 

 seeing what chemical agent would be best suited for the purpose. 

 Subsequently, at his suggestion, Mr. Crookes was asked to carry 

 on various practical trials which might test the efiicacy of two 

 agents which Dr. Angus Smith had reported to us as likely to be 

 useful. We refer to the reports of these two gentlemen for an 

 explanation of the present doctrines of infection, and an enumera- 

 tion of the different substances which may be used to destroy the 

 poison. On examining these different agents it is soon found that 

 the number of those which can be employed with advantage is 

 limited. Since the poison is constantly given off in discharges 

 flowing from diseased surfaces, and since it may be suspended like 

 impalpable dust in the air, it becomes necessary that any disinfec- 

 tant should act continuously both on the discharges and on the air. 

 No disinfectant can be efficacious if its action is intermittent, or if 

 it does not act on both sources of danger. It is evident indeed 

 that the poison ought to be destroyed at the very moment of evo- 

 lution or discharge. Every minute during which it remains active 

 increases the danger. The disinfectant must therefore not only be 

 both fixed and volatile, but so cheap and easily used as to be con- 

 tinually in action, and it must of course be innocuous to cattle and 

 men. A large number of substances which can be used in many 

 other cases as disinfectants, must be put aside, as not meeting 

 these necessary conditions. Compounds of iron, zinc, lead, mai> 



