56 BULLETIN 780, IT. S. DEPARTMENT OF AGRICULTURE. 
SUMMARY AND CONCLUSIONS. 
The following statements concerning Nosema-disease seem to 
be justified from the facts recorded in the present paper: 
(1) Xosema-disease is an infectious disorder of adult bees caused 
by Nosema apis. 
(2) The disease is not particularly malignant in character, being 
in this respect more like sacbrood than the foulbroods. 
(3) Adult workers, drones, and queens are susceptible to infec- 
tion, but the brood is not. 
(4) The infecting agent Nosema apis is a protozoan that attacks 
the walls of the stomach and occasionally those of the Malpighian 
tubules. 
(5) A colony can be inoculated by feeding it sirup containing 
the crushed stomachs of infected bees. 
(6) One-tenth of the germs present in a single stomach are sufficient 
to produce marked infection in a colony. 
(7) Within a week following the inoculation the parasite can be 
found within the walls of the stomach. 
(8) Before the close of the second week infection can be determined 
by the gross appearance of the organ. 
(9) The disease can be produced at any season of the year by feed- 
ing inoculations. 
(10) Infected bees may be found at all seasons of the year, the 
highest percentage of infection occurring in the spring. 
(11) Nosema infection among bees occurs at least in Australia, 
Switzerland, Germany, Denmark, England, Canada, and the United 
States. This distribution shows that the occurrence of the disease 
is not dependent altogether upon climatic conditions. 
(12) The course of the disease is not affected directly by the 
character or quantity of food obtained and used by the bees. 
(13) A sluggish body of water, if near an apiary and used by bees 
as a water supply, and the robbing of diseased colonies, must be 
considered for the present as two probable sources of infection. 
(14) The transmission of the disease through the medium of flowers 
is not to be feared. 
(15) The hands and clothing of the apiarist, the tools used about 
an apiary, and winds need not be feared as means by which the 
disease is spread. 
(16) Hives which have housed infected colonies need not be dis- 
infected and combs from such colonies are not a likely means for the 
transmission of the disease. 
(17) Bees dead of the disease about the apiary are not likely to 
cause infection unless they serve to contaminate the water supply. 
(18) Nosema apis suspended in water is destroyed by heating for 10 
minutes at about 136° F. (58° C). 
