SACBROOD. 49 



tively small quantity of more or less clear liquid. The scales formed 

 by the drying of the decaying remains are easily removed from the 

 cells. After becoming quite dry many of them indeed .can be shaken 

 from the brood comb. 



Upon crushing larvae which have been found dead for some time but 

 not yet dry, a marked unpleasant odor will be noticed if the crushed 

 mass is held near the nostrils. 



Microscopically no microorganisms are to be found in the decay- 

 ing: remains of the larvse. Cultures made from them are also nee;- 

 ative. 



Differential diagnosis. — Sacbrood must be differentiated from the 

 other brood diseases. 



American foulbrood may be recognized by the peculiar odor of the 

 brood combs when the odor is present. The body wall of the larval 

 and pupal remains is easily ruptured, and the decaying mass becomes 

 viscid, giving the appearance popularly referred to as "ropiness." 

 The scale adheres quite firmly to the floor of the cell. The presence 

 of Bacillus larvse in the brood dead of the disease is a positive means 

 by which it may be differentiated from sacbrood. 



European foulbrood may be recognized by the fact that the larva? 

 as a rule die while coiled in the cell and before an endwise position is 

 assumed. In the majority of instances, therefore, death takes place 

 before the cells are capped. The saclike appearance characterizing 

 the dead larvse in sacbrood is absent. The granular consistency of 

 the decaying mass is absent also. Microscopically, a large number of 

 bacteria are found in larvse dead of European foulbrood, but are 

 absent in larvse dead of sacbrood. The presence of Bacillus pluton 

 is a positive means by which European foulbrood may be recognized. 

 Bacillus alvei and other species may also be present. 



Sacbrood must also be differentiated from other conditions re- 

 ferred to as chilled brood, overheated brood, and starved brood, 

 which occasionally are encountered. This can be done by a compar- 

 ison of the symptoms presented by these different conditions with the 

 symptoms of sacbrood, and the history of the cases. Some of the 

 larvse dead from these conditions will be found to have died while 

 yet coiled in the cell. This fact suggests some condition other than 

 sacbrood. When dying later, the saclike remains characterizing sac- 

 brood are not present in conditions other than sacbrood. 



PROGNOSIS. 



The tendency in a colony affected with sacbrood is to recover from 

 the disease. Colonies which during the spring months show the pres- 

 ence of more or less disease, by midsummer or earlier may, and very 



