308 Pellagra-Producing Diets. IV 
numbers of young is to be fostered. Animals, which have been 
restricted to inadequate and monotonous diets, have in our ex- 
perience been subject to infections of the lungs and to a condition 
suggestive of bronchitis, one or both of which constitute the 
terminal event in the lives of the animals. Xerophthalmia is 
seen in those animals whose diet lacks an adequate amount of 
the fat-soluble A and beri-beri when there is a shortage of water- 
soluble B. Poor condition of the hair, with varying degrees of 
baldness in some cases, an incrustation of the ears, irritation of 
the skin, excessive development of warts, especially on the nose 
and tail, extreme timidity in certain animals brought to a state 
of malnutrition which in many instances was manifest only in 
failure to grow, in others by loss of hair and unthrifty appearance, 
as well as timidity, are common observations in our rat colony, 
where many types of faulty diets have been employed. Height- 
ened resistance to disease is one of the outstanding features in 
those groups of our animals whose diets are of such a character 
as to induce rapid and sustained growth in the young. 
Those who select their food solely with a view to economy as 
respects cost, find in the literature concerning foods the informa- 
tion that the cheapest sources of both energy and protein are the 
cereal grains, and the legume seeds, peas and beans. Economic 
conditions are now such that rigid economy is necessary in the 
purchase of food, especially among city dwellers with small in- 
comes. Unless the public is speedily educated regarding the 
necessity of employing regularly in the. diet either an appropriate 
amount of milk or of the leafy vegetables, it seems certain that 
the time is not far distant when dietary errors now becoming 
common will become a still more important menace to the public 
health. . 
.. The necessity of increasing the content of sodium, chlorine, 
and calcium in a diet principally derived from seeds before 
growth can proceed, affords a striking example of the depend- 
-ence of the growing animal on an appropriately constituted in- 
organic mixture as a foundation upon which to superimpose a 
suitable organic ration. The necessity of an adequate supply of 
those elements which constitute the ash left. on incineration. of 
the animal body has been appreciated since the early experi- 
ments of Lunin (9) and of Forster (10) with ash-free diets.. It 
