K. C. SEN AND P. A. SESHAN                       173

Govt. Agric. Chem. Coimbatore, 1932-33). Vegetables had their carotene
content markedly increased by a fertilization of the soil with nitrogen, phos-
phate and potash. Irradiation by neon light of parsley, chive and spinach
increased their yield and vitamin-A content [Pfutzer and Pfaff, 1935].

Several attempts have been made to estimate the carotene content of
some of the commoner pasture plants in their fresh green stage. Timothy
grass contained 200±13 Sherman units per grm. of fresh material, red top
308±10, smooth brome grass 396±27, alfalfa 269±17, white blossom sweet
clover 242±19 and 500±30 respectively in the second and first years, orchard
grass 275±13 and meadow fescu 250±13. Based on these results it has
been advised that dairymen could select any mixture of pasture plants adapted
to their particular climatic and soil conditions without any risk of producing
a vitamin-A deficiency [Woods, et al, 1935, 1935-a, 1935-b]. In making an
estimate of the vitamins in the diet of pigs, the vitamin-A contents of air-
dried rye grass and sun-cured pasture hay have been put down as 3,500 and
1,000 international units per 100 grm. [Cunningham, 1936].

                          VITAMIN-A REQUIREMENT OF ANIMALS

We have so far concerned ourselves with avitaminosis-A and the possible
sources through which it can be averted in so far as it relates to animal nutri-
tion. The effect of providing the animal with its normal requirement of
vitamin-A would just enable the animal to have its proper health, growth
and production. It is, therefore, desirable to obtain an idea as to the require-
ments of the various animals for carotene or vitamin-A for prophylactic and
curative purposes.

To prevent and cure xerophthalmia in rats on a vitamin-A deficient
diet, it was found sufficient to give a daily dose of 0.5 to 1.0 γ of three different
specimens of carotene. Other workers found that 2 to 5 γ were necessary
[Polak and Stokvis, 1931]. As a result of studies on thirty-one puppies,
depleted of vitamin-A by feeding, it was shown that 114 U. S. P. units per
100 grm. of body weight were required before any appreciable storage could
occur [Frohring, 1935]. The requirements of the fowl per unit of body weight
was observed to be more than that of the rat for growth and maintenance.
Depleted birds of about 400 grm. weight required about 0.05 mg. of caro-
tene daily, while fowls weighing 2,000 grm. had to be given 0.5 mg. For
prophylactic purposes slightly smaller quantities might be sufficient. White
Leghorns required thirty-three Sherman units per pound of live weight every
day for maintenance and 6.3 units to produce one unit of vitamin-A in
the egg yolk, the yolk in an average egg weighing fifteen grm., each grm. of
which would contain twenty units of vitamin-A [Cruickshank, 1935].

Pigs on the other hand have been found to require only small quantities
of vitamin-A. On a vitamin-A free diet they continued in normal health till
the third litter. Pigs born at this stage failed to thrive on the same deficient
diet. But young ones born to normally fed parents grew up in proper condi-
tion to the fattening stage, even on a vitamin-A free diet. Green fodder or