Apr. 12, 1924 
Development of American Foulbrood 
159 
sary for the formation of the stored glycogen and fat, on the basis of the relation 
of their carbon atoms. 
Molec - 
For - ular 
mula weight Equivalent sugar per cent 
Dextrose (unassimilated)_C 6 Hi 2 O 6 = 180 5 3. 14 
Glycogen.C 5 H 10 O 5 = 162 18 ° 1 ~^ 62 X il 5. 57+5. 57 = 6. 13 
Fat (oleic acid)_C, s H 3 40 a =282 64+3. 64= 5. 38 
Total__ 14. 65 
Since more sugar is used for energy in the production of a molecule of glycogen 
or of a molecule of fat (82, p. 77) than is indicated by the actual relation of the 
carbon atoms, this figure should be somewhat higher, thereby more nearly 
corresponding with the figure calculated from the weight ratio between in¬ 
testine and larva. 
The average concentration of sugar in the food of a larva of the age during 
which inhibition of bacterial growth takes place is 13.48 per cent (40) (Table III, 
fig. 11). The percentage composition of the larva at the different age periods 
(Table IV, fig. 15) in relation to food composition indicates, however, that the 
food probably is not assimilated as rapidly as it is ingested by the larva. If 
this is the case, an increase in the unassimilated sugar in the intestine would 
occur, as is indicated by the results obtained and the calculated percentage 
figures. The percentage of glycogen and fat increases slightly by the third day, 
as a result of the change in the composition of the food and the resulting increase in 
nursing (26 ). This is accompanied by the appearance of unassimilated sugar in 
the larva (Table V, fig. 15). There is then a marked increase by the fourth day, 
when apparently the limit for assimilation is reached, as shown by the constant 
percentage of glycogen in the larva as a whole between the fourth and fifth days 
in spite of the increase in weight, until after feeding ceases, when there is another 
increase in storage during the next 24 hours (sixth day). The latter is the result 
of the consumption of the food remaining in the cell after capping. The amount 
of unassimilated sugar increases continually, however, until feeding ceases, soon 
after the larva is sealed in the cell. This fact probably accounts for the slight 
difference between the percentage of sugar in the food and the calculated per¬ 
centage in the intestine, but the correspondence is so striking as to substantiate 
the assumption. 
Even though these calculations are only approximately accurate, it is known 
that some such condition must exist, since observations which have been made 
on the nursing habits of the honeybee (26), considered in relation to the figures 
for unassimilated sugar and food composition, give adequate foundation to the 
conclusion that there is considerably more than enough sugar in the intestine 
at the time infection occurs, or soon after, to inhibit the growth of the organism 
causing American foulbrood. 
THE ACTIVE FEEDING STAGE IN THE LIFE HISTORY OF THE LARVA 
The feeding stage of the honeybee larva has been divided into two parts, de¬ 
scribed by Lineburg (26) as the mass feeding period and the progressive feeding 
period. These two periods are characterized by a difference in the manner of feed¬ 
ing and in the amount of time spent by the nurse bees in the process, as well as 
by the change in chemical composition and character of the food (40) (Table III), 
and by the chemical composition of the larvse themselves (43) (Table IV). It 
has been determined, however, that this change in composition of food occurs 
6 From Table V. 
8 From Table IV, Straus. 
