KA.NEMATSU SUGIUR.\ AND GIOACCHINO FAILLA 429 



/S-rays. The emanation tube was placed parallel to the length of the 

 animal to obtain a more even distribution of the radiation. Neverthe- 

 less it should be expected that the skin directly under the tube would 

 receive more radiation, especially on account of the curvature of the 

 body. Accordingly, when the dose was sufficiently large, marked 

 local efiferts were produced on the backs or heads of the animals. The 

 results may be summarized as follows: There were no visible changes 

 in the skin and the hair growth of mice exposed to doses of 1.9, 2.4, 

 and 4.7 millicurie hours. A dose of 6.8 milHcurie hours retarded the 

 development of lanugo hair directly opposite the emanation tube, 

 and produced a skin erythema. The growth of hair, however, became 

 normal on the 15th day after birth. Larger doses of radiation pro- 

 duced more pronounced effects. The mice irradiated with 11.5 milli- 

 curie hours had no hair on their backs on the 8th day. The hairless 

 area was completely filled with new hair on the 14th day, but its re- 

 tarded growth could be noticed up to the 30th day. The animals 

 exposed to 21.9 milHcurie hours showed wrinkled and reddened scalps 

 on the 10th day. The radium reaction on the skin became worse up 

 to the 15th day, when it was at its height. The skin was dry, scaly, 

 wrinkled, and hemorrhagic. The eyes were inflamed and almost 

 closed; the ears red, swollen, and underdeveloped. The heaHng pro- 

 cess began at this time and progressed slowly. The effects from 26.8 

 millicurie hours were similar to these but more severe. On the 13th 

 day the mice were unable to run normally, but could get about only 

 with great difficulty. However, the animals gradually regained their 

 health and vigor. A narrow strip of hairless skin, over which the 

 emanation tube had been appHed at a distance of 2 cm. was still 

 visible at the end of the 616 day. Doses of 31.6 and 36.5 millicurie 

 hours caused the mice to die on the 12th and 9th days respectively. 

 Their hind legs were completely paralyzed the day before death. The 

 viscera were very much undersized, and the brains hemorrhagic and 

 congested. 



The age at which the normal mice open their eyes is variable, but 

 generally it is 13 days. Among mice of the same litter, however, 

 there is little irregularity. Female mice often open their eyes a few 

 hours earlier than the males. A record was kept of the age of the 

 individual mice at the time they opened their eyes, and the averages, 



