;380 
Journal of Agricultural Research 
Vol. XXIX, No. 8 
Y represents the weight in grams of 
the intestines and X the gross body 
weight in grams. 
The large paired caeca are also 
included with the weights of the 
intestine. A comparison of the charts 
in Figures 15 and 16 shows that, while 
the intestines and gizzard grow at very 
nearly the same rate, yet the gizzard 
lags behind the intestines throughout 
the middle part of the curve. This 
would indicate that the intestines 
complete their growth a little earlier 
than the gizzard. 
The three regions into which the 
.digestive tube was divided grow appar¬ 
ently at about the same rate. A com¬ 
parison of the charts (figs. 14, 15, 16) 
will show a marked similarity. The 
relative weight of the intestines com¬ 
pared with the net body weight shows 
a short rise and then a decreasing rate 
of growth until in the adults the intes- 
walls, which were thrown into longi¬ 
tudinal folds. m 
The use of gross or net body weights 
for abscissae and for calculation of 
percentage weights raised the question 
of the amount of tare or contents 
of the digestive tube. For abscissae it 
seemed best to. use the gross weights 
because these are more easily deter¬ 
mined and more generally useful for 
reference; but for calculating percent¬ 
age weights, the net body weight was 
used. It was thought that a corrective 
factor could make possible the con¬ 
version of gross into net weight, or vice 
versa. The absolute and the percent¬ 
age weights of the tare were therefore 
plotted on age, but there appeared a 
surprising variability in both cases. 
As might be expected the increase in 
contents is very rapid at first: 
Just after hatching and for the suc¬ 
ceeding three days the absolute weights 
Fig. 15.—Absolute and relative or percentage weights of the empty gizzard. The heavier line represents 
the weight in grams. The lighter line shows the percentage of the net body weight 
tine forms about 2 per cent of the 
net body weight. This short initial 
increase in percentage weight is found 
also in the pancreas, liver, and kidney, 
all organs concerned with nutrition and 
excretion, which up to this time have 
been carried on by the yolk sac and 
allantois. It looks as though these 
organs made a rapid growth to meet 
the demands of the organism as soon 
as it had to provide for itself. The 
proventriculus or glandular stomach 
does not show this early rapid growth. 
Contents of digestive tube. —In 
connection with the digestive tube may 
be mentioned the contents found there¬ 
in. The stomach never contained 
much food and usually showed none, 
while all the other parts of the canal 
(from crop onward) were generally 
more or less filled. In the stomach or 
proventriculus was always found a 
characteristic whitish mucus lining the 
are: 0.7, 1.4, 3.7, and 6 gm. Until a 
little after the one hundredth day the 
variation in absolute weight of the 
tare is not great, but after that day 
the range is from 30.9 gm. to 160.9 gm. 
The relative weights for the first six 
days following the date of hatching are: 
2.3, 3.95, 12.1, 15.8, 14.3, 18.2, and 
19.3 per cent, reaching the maximum 
found in any specimen. While the 
cases are very irregularly arranged, 
their average slowly falls after the 
sixth day to about 4.5 per cent of 
tare for the adults. The use of this 
number as a means of changing from 
gross to net body weight would give 
only approximate results, however, for 
the variation is very great. 
A part of the tare in the fowl is 
the gravel in the gizzard. In a major¬ 
ity of the older chickens, some grit or 
small stones appeared in the large 
intestine. Why they should be more 
