632 MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



bacterium is quite resistant to drying, but is rather sensitive to sunlight. 

 It is usually destroyed by moist heat in six hours at 55; in twenty minutes 

 at 60; and generally in two to five minutes at 95, depending upon the 

 protection it may have. 



Conditions of sensible sanitation are of the utmost importance. These 

 include exercise, sunlight, and ventilation, particularly sunlight. In 

 order that effective control work may be done, tuberculin must be used 

 freely and conscientiously. 



The method of dealing with diseased herds depends upon breeding 

 and value. Common cattle are usually dealt with most economically 

 and efficiently by slaughter with a view to using such carcasses as may 

 pass inspection. Valuable cattle, especially pure bred animals, may be 

 used for breeding purposes, gradually building up a sound herd and 

 gradually displacing the diseased animals. This latter plan is usually 

 unprofitable and unwise except for valuable cattle. 



FOOT ROT OF SHEEP.* 

 Bacillus necrophorus. 



This is an infectious disease of sheep characterized by an ulcerative in- 

 flammation of the tissues just above the horny part of the cleft of the hoof. 

 It is seen in Europe, England, Australia, and the United States. Sheep 

 are made lame and if the disease is not checked by appropriate treatment, 

 the hoof becomes greatly distorted, the sheep being finally unable to walk. 

 Mohler and Washburnf state that foot rot is caused by B. necrophorus, 

 this organism being associated with pus-producing micrococci. B. 

 necrophorus, which is a strict anaerobe, tends to grow out into long 

 filaments; it is stained by the ordinary aniline dyes, but not by Gram's 

 method. Rabbits and white mice are susceptible to inoculations of this 

 bacillus, but guinea pigs appear to be immune. The disease is treated 

 by causing infected sheep to walk through a disinfecting solution, such 

 as a 3 per cent solution of carbolic acid. 



FOUL BROOD OF BEES.| 

 Bacillus alvei. Bacillus larva. 



This disease has been known since the time of Aristotle. It was 

 well described by Shirach in 1769, who gave the malady its popular name, 



* Prepared by M. Dorset. 



t Bulletin 63, Bur. An. Industry, U. S. Dept. Agr., 1904. 



t Prepared by F. C. Harrison. 



