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 apis to the ‘‘virulent’’ type 
of dysentery. 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 of 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 summary 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 this 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 believes the mild form to be noninfectious and probably due 
to a number of different causes; the infectious or virulent form he 
believes to be due to Nosema apis. 
4. He is inclined to believe that this infectious form is the same 
disorder as the one to which ‘‘May disease” and ‘‘June disease’”’ has 
frequently been applied. 
5. Itshould be noted that Zander does not claim to be working with 
anew disease, but is simply seeking to determine the cause of dysen- 
tery—a disease with which most bee keepers have had experience. 
