42 



important factors besides the mere introduction of the infect- 

 ing agent, though of course, Nosema disease cannot arise 

 urJess Nosema is introduced. Every infected bee dies sooner 

 or later in consequence of the infection, but parasites some- 

 times occur in small numbers and reach the spore stage with- 

 out apparently affecting the health of the bee. Old spares 

 from dead bees seem to be less virulent than fresh spores 

 from bees recently dead of the disease, and there is some 

 reason for believing that while unsuitable food, and damp or 

 unhealthy conditions, are favourable to the more ready 

 development of the parasite, suitable feed and favourable 

 conditions increase the natural resistance of the bees, and, 

 at least for a time, keep the sympto^ms of the disease in 

 check. Requeening at regular intervals, if practised 

 systematically, is a valuable aid in combating disease. 



In comparison with Acaxine Disease the following conclu- 

 sions are interesting r — 



1. There is a disease produced by Noae-ma which is 

 infectious. 



2. That although Nosema may be present it does not always 

 produce the characteristics of Aoarine disease (so called " Isle 

 of Wight " disease), and that this disease may exist without 

 NosemA being present. 



3. Drs. Graham- Smith, Pantham and Porter found no spores 

 of Nosema in 13 out of 66 cases of " Isle of Wight " disease 

 investigated. If Nosema were the cause of the disease it 

 should have been found in every case. 



4. Crawling is one of the chief characteristics of Acarine 

 disease, whereas Nosem,a may be present in large numbers 

 without the bees showing any signs of crawling. 



5. Infection with Nosem,a does not produce the charac- 

 teristics of Acarine disease. 



6. In Nosema disease the colony may appear healthy, the 

 only symptom being the heavy mortality of bees. 



7. In Acarine disease "crawling" is one of the chief 

 characteristics. Dr. Porter has stated that in some bees show- 

 ing the " crawling " symptoms and sent for diagnosis no 

 Nosema was found. Dr. Graham-Smith also found nothing 

 special in bees sent to him from a crawling colony. 



8. Dysentery, frequently present, but not invariably 

 evidenced in Acarine disease is not a primary symptom, and 

 may be due to other causes. 



9. In Acarine disease the queen is often the last to succumb, 

 while in Nosema she may be amongst the early victims. 



Acarine Disease. 



In the past few years investigations have been carried out 

 in Aberdeen under Dr. John Eennie, which have resulted in 

 the discovery of a parasite belonging to the genus Tarsonemus, 

 hitherto unknown in bees. 



