1018 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
aerated daily, care being taken to avoid a temperature greatly in 
-excess of its melting point. When the lard was sufficiently rancid, 
as indicated by the Kreis test and its odor and taste, the feeding 
experiment was begun. 
EXPERIMENT 1 
The rations employed in experiment 1 were made up as follows, 
the components being intimately mixed in a mortar: 
Per cent 
Dry commercial casein_ 14 
Cassava starch_ 53 
Dried baker’s yeast_ 10 
Dried egg yolk_ 3 
Salt mixture (Drummond and Watson’s formula 2 )_ 4 
Lard (sweet or rancid)_ 16 
100 
The sweet fat employed gave a negative Kreis test, and a negative 
test for peroxides, and contained 0.18 per cent of free fatty acids cal¬ 
culated as oleic acid. The rancid fat gave a positive Kreis test when 
diluted with 25 parts of pure mineral oil, and an intense test for 
peroxides, and contained 2.76 per cent of free fatty acids calculated 
as oleic acid. 
Twelve rats were used in this experiment, six of which received the 
sweet fat and six the rancid. Their ages and weights at the begin¬ 
ning of the experiment, together with tneir respective sexes and litter 
numbers, are indicated in Table I. 
Table I .—Description of rats used in experiment 1 
Rat 
No. 
Ration 
Sex 
Initial 
age 
Triitial 
weight 
Litter 
Rat 
No. 
Ration 
Sex 
Initial 
age 
Initial 
weight 
Litter 
1 
Rancid... 
Female- 
Days 
32 
Grams 
45 
69-C 
7 
Sweet_ 
Male_ 
Days 
32 
Grams 
41 
69-C 
2 
_do_ 
Male_ 
32 
46 
69-C 
8 
...do. 
Female- 
33 
„ 39 
69-D 
3 
_do_ 
Female . 
32 
48 
69-C 
9 
_do.. 
Male_ 
33 
40 
69-D 
4 
_do_ 
...do. 
32 
48 
69-C 
10 
...do.. 
...do_ 
34 
40 
69-B 
5 
...do.. 
Male_ 
30 
52 
70-B 
11 
...do_ 
Female... 
30 
50 
70-B 
6 
...do_ 
_do_ 
30 
49 
70-D 
12 
...do_ 
_do_ 
30 
40 
70-D 
During the earlier stages of the experiment the rats receiving the 
rancid lard seemed to suffer from a mild diarrhea, indicative of 
intestinal irritation, but this symptom gradually subsided as the 
experiment progressed. In general, also, as is shown by the growth 
curves in Figure 1 and by the record of total food consumption in 
Table II, the rats of the rancid series consumed less ration and gained 
less weight than the corresponding controls. Finally, on the eighty- 
eighth day of the experiment rat No. 3 developed ophthalmia, and 
on the same day the experiment was terminated. 
At the end of the experiment a blood count was made on rat No. 
5, which was in the poorest condition of all the rats receiving the 
rancid lard, and on rat No. 10, which received the sweet lard. No 
essential difference was noted in the number of red cells in the blood 
2 Drummond, J. C., and Watson, A. F. the testing of foodstuffs for vitamins. Analyst 47: 237. 
1922. 
