MICROBIAL DISEASES OF MAN AND ANIMALS. 633 



and suggested a method of cure almost identical with that used at the 

 present day. In 1886 Cheshire and Watson Cheyne showed that the 

 disease was caused by a bacillus, to which they gave the name B. alvei. 

 In 1906 White isolated an organism from diseased bee larvas, which he 

 called B. larva, which does not grow on the ordinary culture media, and 

 hence had escaped the attention of various workers. The name of 

 "American foul brood" has been suggested for this disease, but the 

 choice of this name seems unfortunate, because it is claimed that B. 

 larvcs is the organism which produces the typical symptoms described 

 by investigators in Europe. 



The disease principally affects the larvae, which in the early stages of 

 the attack move about unnaturally or lie extended instead of curled up 

 in the cells. As the disease progresses they become flabby, die, and then 

 decomposition sets in, which is shown by a yellowish appearance, and 

 finally this color turns brown ; if touched by a pin the putrid mass may be 

 pulled out as a ropy tenacious string. Later, the ropy mass dries down 

 to the bottom of the cell, leaving a brown scale which adheres to the wax. 

 Bees occasionally become diseased and die, and B. alvei has been isolated 

 from the ovaries of the queen bee. 



B. alvei is a slender bacillus with slightly pointed ends, average 4.0/1 in length and 

 i.o/x in breadth, forms chains, is Gram-positive, forms spores greater in diameter than 

 the cells from which they are derived. Produces characteristic colonies in gelatin, 

 which is subsequently liquefied and grows well on all the regular media. 



B. larva is a slender rod, with a tendency to form chains; it forms spores, does not 

 grow in gelatin broth or agar. It may be grown on media made from bee larvae. 



There are three methods of controlling the disease: Stamping-out 

 method. In this method all affected bees, combs, and frames are destroyed 

 and the hives thoroughly disinfected. 



Starvation method. This process is the one usually followed in North 

 America. It consists of removing the combs from the hives in the 

 evening, shaking off the bees and supplying them with new comb 

 foundation starters and allowing the bees to build on these for four 

 days. These combs are then renewed, fresh comb foundation is again 

 supplied, and the cure is usually completed. By this method of treat- 

 ment all the diseased honey and brood are removed from the hives. 

 All the old combs should he burned or made into wax. 



Treatment by chemicals. This method is largely used in Europe; 

 various chemicals, like carbolic acid, oil of eucalyptus, beta-naphthol, 



