Localized Lesions Produced by Buried Radium. 381 



during the summer are incomparably richer in ultraviolet than 

 those during the winter and early spring. It seemed, therefore, 

 of interest to follow, month by month, the content of inorganic 

 phosphate in the blood of a group of infants, where dietetic and 

 hygienic conditions could be controlled. The accompanying 

 tables indicate the result of a systematic study of this kind. 

 Table I shows that in June and July of last year the average in- 



table 1. 



Seasonal Tide of Blood Phosphate (Inorganic), 

 june july aug. 8ept. oct. nov. dec. jan. feb. mar. apr. may 



organic phosphate of the blood of these infants, who varied in age 

 from about 6 to 18 months, was 4.35 mg. per cent. During the 

 summer and fall analyses were not carried out. In December 

 the average percentage had fallen to 3.92 mg., and then decreased 

 steadily during January, February and March. In April, espec- 

 ially during its latter half, and in the first half of May, the inor- 

 ganic phosphate again began to rise. These averages represent 

 some 270 individual tests. Table II shows that the high percent- 

 ages in the summer and the fall, and the steady and marked ebb 

 during the winter months, occur quite irrespective of the nature 

 of the diet. This seasonal tide of the blood phosphate is to be 

 attributed mainly to the seasonal variation of sunlight. It would 

 seem that the ultraviolet rays are necessary for the normal metab- 

 olism of the growing infant, especially in relation to its exchange 

 of inorganic salts. 



