EUROPEAN FOULBROOD. 91 
RESISTANCE OF BACILLUS PLUTON IN HONEY TO DIRECT 
SUNLIGHT 
Experiments were made to determine the resistance of Bacillus 
pluton when suspended in honey to the direct rays of the sun. 
In these experiments a honey suspension of the organism obtained 
from the stomachs of infected bees is exposed to the sun in a 
Petri dish with the top removed. After intervals, reckoned in hours, 
inoculation tests are made using healthy larve and the direct 
method. Table VIII contains a summary of the experiments per- 
formed : 
TABLE VIII.—Resistance of Bacillus pluton suspended in honey and exposed 
to direct sunlight 
Period 
Date of inoculation. of Results of inoculation. 
exposure. 
1915. Hours. 
AN OR DAN in Seem tye aioe Sete aia arian as ats a Ae 5 Slot OR ii ncy ec cia 1 | European foulbrood produced. 
ADD) ORS rete yo Sess Seine aw aie athe ais ele ete estas we miemioake siniels 2 Do. 
AD) Qe emcee Se CREE ie onions nnSie sivas wee eiciedcts are 3 Do. 
AN Coep 3 Waa elles faear ee ielee ees eo at RI te SNe Selle een ee 3 | No disease produced, 
SAN 252 0 eerste ei oieisise eles erro ites er eine ic ciaieieiaiiciere 3 Do. 
DOD Uap Series Nose eee mets icra Spat a seis cle /oies/ajeisias 3 Do. 
PO PD eel Ore stever ens cesree ate ees er eicisiciaistele Mier nelasineibine iscisiccis wis, csrepe'e 4 Do. 
PANS 2O BS et te eM eee a Re ene Pics Says t ian be cai 5 Do. 
SSG ied a ce operate ey crenata ote Sas ee ci tcxalomrsciclotnts eiciaueainicinraicreioisiniere 5 Do. 
PR crenata hat any spe ges itn a Sinai otecs aise nin inte SD hinisa ee lclsis 6 Do. 
tSIG) Olio JU le Se eS NRC A BOSOM eee See LCc ener Rice iret ae aie 7 Do. 
FSIS) ORT 3 8 SU EN 8 a Se ee a ee 8 Do. 
bcs dae GSS ase a oo suo o dost EaiE BOSE Se Sees aaa ce te ase 9 Do. 
RIOD ase eee temic ce ear een cee itobec.s cee meee Re eRe Reet 10 Do. 
It is shown by the experiments recorded in Table VIII that in 
direct sunlight Bacillus pluton was destroyed in from 8 to 4 hours. 
The results obtained by the experiments summarized in the last 
three tables above, it will be noted, show that Bacillus pluton is sus- 
ceptible to the destructive effects of the direct rays of the sun; that 
the resistance of the organism suspended in honey is about equal to its 
resistance when suspended in water; and when dry the resistance is 
considerably greater than when suspended in either water or honey. 
It is to be expected that the period required for the destruction of the 
organism by the rays of the sun will vary with the intensity of the 
rays at the time of the exposure. In the foregoing experiments clear 
days were chosen and preference was given to the middle of the day 
for the exposures. 
RESISTANCE OF BACILLUS PLUTON TO FERMENTATION 
In obtaining data relative to the resistance of Bacillus pluton to 
fermentation, the stomach contents of larve sick or recently dead of 
European foulbrood were suspended in a 10 per cent sugar (saccha- 
