It is an established fact that the fat soluble vitamin is necessary in the ration. Drummond1 reported a lowered resistance to infection in rats deprived of this vitamin. He found, however, no specific pathologic change on gross examination of grown or half grown rats. Emmett2 states also that in a histologic examination of rats fed a ration deficient in the fat soluble vitamin he found the tissues normal. He does not give the age of the animals.
On the other hand, Tozer3 found that young guinea-pigs on a ration deficient in the fat soluble vitamin, even with an excess of the antiscorbutic vitamin, develop enlargements of the costochondral junctions very similar to the beadings of scurvy.
M. Mellanby,4 who worked with puppies, found that the fat soluble vitamin controlled the calcification of the teeth. With a ration of white bread and 200 c.c. skimmed milk daily,