The authors already described about the influence of ultra-violet ray upon the milk production of cow whose udder was irradiated as the first report of this main subject on Vol. III, No. 3, 1928 of this Journal.
Now in this paper the authors are going to abstruct the experimental results of Expt. 2 (Influence of ultra-violet ray upon the milk production of cow whose food was irradiated.) and Expt. 3 (To discover the quantities of CaO and P2O5 in the milk afforded by the cow whose udder was irradiated.) as follows:
1. When ultra-violet ray was irradiated upon the cow's food keeping at the distance of 60cm. from the source of light for one and half hours per day while the contents of food were stirred up two times every 30 minutes, there was an increase of 2.92% of the total milk weight and 4.24% of the total butter fat weight in the average of the two cows.
2. The irradiation of ultra-violet ray not only on the concentrated food but also on corn silage was very effective in increasing the milk production of a cow. And though it was an experiment upon only one cow there was an incraese of 28.4% of milk and 15.9% of butter fat.
3. The constituents of CaO and P2O5 in the milk of cows are scarcely changed by the irradiation upon their udders each 30 minutes per day keeping at the distance of 25cm. from the source of ultra-violet ray from the hind and both sides of their udders.