SACBEOOD, A DISEASE OF BEES. 3 



diseased. He placed the results of his examinations under the follow- 

 ing headings : " Sour brood," " stinking foul brood," " nonstinking 

 foul brood," and " dead brood free from bacteria." Four of the 25 

 samples examined contained dead brood free from bacteria and unac- 

 companied by other diseases. Kiirsteiner, of Switzerland, in 1910, 

 in classifying the results obtained from samples examined by him, 

 made the same classification as made by Burri. During the past six 

 years 326 samples of this disease have been received by the Bureau 

 of Entomology and diagnosed in its bacteriological laboratory. 



There is, therefore, a disorder attacking the brood of bees in which 

 brood dies, but in which there has not been demonstrated any micro- 

 organism to which the cause of the trouble could be attributed. For 

 this disease the name of " sacbrood " is here suggested. 



THE NAME SACBROOD. 



As stated, my first examination of this dead brood was made in 

 1902, when samples were received diagnosed by bee keepers as 

 " pickled brood." The fact was easily determined at that time that 

 the disease could not be considered a fungous disease and was there- 

 fore not pickled brood. In the past my preference has been to refer 

 to this condition only as the " so-called pickled brood." Since the 

 disease is not pickled brood, it will produce less confusion and be 

 more scientific if the term " pickled brood " be entirely omitted in 

 the name for the disease. Many larva^ dead of this disease can be 

 removed from the cell without rupturing their body wall. AAHien 

 thus removed they have the appearance of a small closed sac. This 

 character suggested the name " sacbrood.'" The name has the virtue, 

 therefore, of being both appropriate and brief. 



THE SYMPTOMS OF SACBROOD. 



The strength of a colony in which sacbrood is present is frequently 

 not noticeably diminished. When the brood is badly infected, how- 

 ever, the colony naturally becomes appreciably weakened thereby. 

 The brood dies after the time of capping. The dead larvae are there- 

 fore almost always found extended lengthwise in the cell and lying 

 with the dorsal side against the lower wall. It is not unusual to find 

 many larva? dead of this disease in uncapped cells. Such brood, 

 hoAvever, had been uncapped by the bees after it died. In this disease 

 the cappings are frequently punctured by the bees. Occasionally a 

 capping has a hole through it, indicating that the capping itself had 

 never been completed. A larva dead of this disease loses its normal 

 color and assumes at first a slightly yellowish tint. " Brown " is the 

 most characteristic appearance assumed by the larva during its decay. 

 Various shades are observed. The term " gray " might sometimes 

 appropriately be used to designate it. The form of the larva dead 



