Isle of Wight Disease in Hive Bees. 61 
nothing was known of Nosema, and therefore I was unaware of any risk, and 
used the combs from which the bees had disappeared, when restocking the 
apiary with purchased bees, and ‘nothing happened.’ ” 
Beuhne is of opinion that “under ordinary conditions, that is, conditions 
favourable to bees, the parasite is merely a casual inhabitant of the intestine 
of the bee.” 
GENERAL CONCLUSION REGARDING INFECTIVITY. 
The general conclusion to which the foregoing facts point is that Isle of 
Wight disease, although probably an infectious disease, is one which requires 
the coincidence of other and presently unknown external factors (besides a 
specific organism) before the disease develops. The disease is not necessarily 
conveyed by mere contact with contaminated hives or combs, or by feeding 
upon contaminated stores. 
EXPLANATION OF PLATE. 
Fie. 1. Section of the chyle-stomach of a bee displaying symptoms of Isle of Wight disease. 
Spores of Nosema are not present, and no young forms were found in this outbreak. 
x 180 (Iron-hematoxylin), 
Fie. 2. Section of the chyle-stomach of a bee infected with Nosema, but not suffering from 
Isle of Wight disease. The stained spore contents came out as black dots in the 
photograph. x 180 (Iron-hzematoxylin), 
Fie. 3. Portion of the teased chyle-stomach of a bee, showing detached cells, some contain- 
ing spores of Nosema. Fresh preparation. x 180. 
Fie. 4. Fresh unstained preparation, showing Nosema spores lying free i in the gut. x 180. 
Fig. 5. This shows the behaviour of a stock (E14) suffering from Isle of Wight disease. 
Note the bees, incapable of flight, clustering on the hive front. Large numbers on the 
grass cannot be seen, but some can be observed climbing up the leg of the hive. 
cs. Chyle-stomach of bee. 
é.  Hpithelium lining chyle-stomach, 
sp, Spores and epithelium of chyle-stomach. 
(Issued separately, 14th September 1916.) 
