sept. 3t 1918 Comparative Toxicity of Cottonseed Products 
435 
With pigs from 10 to 50 per cent of cottonseed meal has been fed. 
The usual experimental diet at this Station has been cottonseed meal 
25 parts, corn or corn meal 75 parts. This diet soon causes pigs to di¬ 
minish their food intake, and serious results will ensue if the pigs are 
kept on this ration. Deaths occur frequently after five weeks. Un¬ 
doubtedly, even with no toxic factor present, a severely restricted diet 
of this type, as corn with other protein supplements, such as soybean 
meal, peanut meal, etc., is inadequate for normal growth and reproduc¬ 
tion of pigs. It would appear from the insufficiency of a vegetarian 
diet that rats would also fail to make normal growth in diets of this type; 
compare Slonaker (6) and McCollum et al. (5, 6). 
A few experiments with rats have confirmed this opinion, and from 
the improvement of animals when given salts and butter fat it would 
appear that rations of this type contain an unsuitable inorganic basis 
and insufficient amounts of the fat-soluble A. This seems to be in 
harmony with our knowledge of the common seeds which have been 
studied by McCollum and his associates. 
Thus, young rats on cottonseed meal and corn meal (1:3) failed to 
grow and ultimately died, but not sooner than rats on soybean meal and 
corn meal fed in the same proportion. Some older rats maintained their 
weight for 40 days, but also finally failed. 
The addition of calcium, sodium, and chlorin, elements in which the 
ash is very poor, and the addition of butter proved beneficial after 
some of the survivors had begun to decline. 
These experiments with soybean meal were conducted to aid in the 
interpretation of the cottonseed experiments. The percentage of protein 
and the inorganic content of soybean meal are very similar to that of 
cottonseed meal. 
Experiments (unpublished) with pigs by the Animal Industry Division 
of this Station have shown that soybean meal is vastly superior to cot¬ 
tonseed meal for pigs; still, when the animals are confined to pens and 
restricted to corn and soybean meal, the appetite is impaired after several 
months, and a sort of pathological lameness and stiffness of the legs 
appears. 
The facts stated above show that these protein concentrates in re¬ 
stricted diets may ultimately cause failure. This phenomenon is, in our 
experience, entirely distinct from the sudden death of pigs on cottonseed 
meal, which may follow excellent growth. 
EXPERIMENTS WITH RABBITS 
Rabbits have been used extensively for experimental feeding of cot¬ 
tonseed products at this Station. The general methods of feeding were 
described in our previous article ( 16 ). Under our conditions young rab¬ 
bits grew rapidly and grown rabbits fattened or maintained weight on 
