90 HISTORICAL NOTES ON BEE DISEASES. 



and the old bees are rapidly replaced by young healthy ones, the 

 young bees remain healthy unless a second infection takes place. It 

 is suggested that if this second infection takes place it asserts its pres- 

 ence about four weeks after the first outbreak. It is then commonly 

 thought by the bee keeper to be a different disease, the one to which 

 the name "May disease" is sometimes applied. In the so-called 

 "June disease" Zander reports the presence of infection with Nosema 

 apis also. 



Zander performed some inoculation experiments for the purpose of 

 demonstrating the relation of Nosema ajns to the "virulent" type 

 of dysenteiy. He describes one in which infected material was fed in 

 honey to a colony free from disease. The excrement from bees affected 

 with dysentery, together with bees so affected, was ground and added 

 to diluted honey. The mixture was filtered and put into two combs, 

 and the combs were placed into a queen-right colony, which had been 

 examined and found to be free from disease. Three days later the 

 bees began to die with all the symptoms of "May" and "June" 

 disease. Many dead and dying bees were found in the yard in the 

 direction of flight oi the bees. A microscopic examination demon- 

 strated the presence of Nosema apis in these bees. After eight days 

 the mid-gut of most of the diseased bees was milk-white. The colony 

 became weaker and weaker, and at the end of a month only a hand- 

 ful of bees remained. 



Zander concludes from his work that Nosema apis is the exciting 

 cause of the infectious form of dysentery. 



The following is a brief summaiy of Zander's first paper on Nosema 

 apis and the disease with which he found it associated: 



1. Zander discovered a protozoan that attacks the epithelial cells 

 of the mid-gut of the adult honey bee. To tliis protozoan was given 

 the name Nosema apis. 



2. He discusses dysentery of bees under two forms — a mild form 

 and a virulent one. 



3. He beheves the mild form to be noninfectious and probably due 

 to a number of different causes; the infectious or virulent form he 

 beheves to be due to Nosema apis. 



4. He is inclined to believe that this infectious form is the same 

 disorder as the one to wliich "May disease" and "June disease" has 

 frequently been applied. 



5. It should be noted that Zander does not claim to be working with 

 a new disease, but is simply seeking to determine the cause of dysen- 

 tery — a disease with which most bee keepers have had experience. 



