42 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



BICHLORID OF MERCURY. 



This is a white crystalline substance which is also known as 

 mercuric chlorid and corrosive sublimate. It is usually prepared for 

 use in the form of tablets with ammonium chlorid, which facilitates 

 the solution of the bichlorid in water. The bichlorid is used in so- 

 lution in water in a strength of 1 to 1,000, though solutions 1 to 500 

 may be employed with correspondingly (juicker action on nonspore- 

 bearing bacteria and much more effective action on the spores of 

 bacteria. Bichlorid of mercury is a violent poison, and has the 

 property of combining with albuminoids to form inert compounds. 

 These facts necessarily limit its usefulness as a general disinfectant. 

 It should never be used to disinfect excreta, or substances containing 

 blood or serous fluids. Bichlorid solutions should not be kept in 

 lead or tin vessels, or poured through lead pipes, as the mercury 

 combines with these metals and injures them, besides affecting the 

 germicidal efficiency of the solution itself. 



The chief advantage in the use of bichlorid of mercury lies in 

 its great germicidal power when employed under proper conditions. 

 The disadvantages .are its poisonous nature, its tendency to attack 

 certain metals, and the interference by albuminoids and other or- 

 ganic substances. 



DETAILS OF DISINFECTION. 



In the practical work of disinfection there are three essentials : 

 (1) A preparation of the building that will facilitate reaching or- 

 ganisms of disease. (2) A disinfectant which upon contact can be 

 depended upon to destroy such organisms. (3) A method of apply- 

 ing the disinfectant that will assure the most thorough contact with 

 the bacteria. 



Preparation of Building. Before beginning the use of a disin- 

 fectant it is essential that certain preliminary work be done in and 

 about the stable that is to be treated. The various surfaces, such as 

 ceiling, walls, partitions, floors, etc., should be swept until free from 

 cobwebs and dust. Any accumulation of filth should be removed 

 by scraping. In some cases the woodwork may have become soft- 

 ened and so porous as to be a good medium for the absorption of 

 disease germs. Such woodwork should be removed, burned, and re- 

 placed with new material. 



All refuse, manure, etc., from stable and barnyard should be 

 removed to a place inaccessible to live stock and, if possible, be 

 burned or thoroughly mixed with a solution of chlorid of lime in 

 the proportion of 6 ounces to 1 gallon of water. If the floor is of 

 earth, it will doubtless have become stained with urine and con- 

 taminated to a depth of several inches. In such cases 4 inches or 

 more of the surface soil should be removed and treated as above 

 suggested for refuse and excreta. All earth removed should be re- 

 placed with soil from an uncontaminated source, or better, a new 

 floor of concrete may be laid, this being the most durable and sani- 

 tary material for the purpose. 



Selection and Preparation of the Disinfectant. Having made 

 ready the field of operation, the next consideration should be the se- 



