Prevention of Rickets in Rats by Sunlight. 43 



free organisms could be demonstrated in the aspirated fluid. 

 Polymorphonuclear cells were present in large numbers and 

 phagocytosis was intense. The virulent type D, on the other 

 hand, gains its foothold primarily by reason of the late appearance 

 of phagocytes following its intrapleural injection. 



The occurrence of the low-virulent type G would seem to 

 afford an excellent opportunity for the investigation of the prop- 

 erties or products of secretion which give the parent D type its 

 characteristic of high virulence. 



21 (1768) 



II. The prevention of the development of rickets in rats by sun- 

 light. 



By P. G. SHIPLEY, E. A. PARK, G. F. POWERS, E. V. McCOLLUM 

 and NINA SIMMONDS. 



[From the Department of Pediatrics, Johns Hopkins University, 

 Baltimore, Md., Dept. of Pediatrics, Yale University, New 

 Haven, Conn, and School of Hygiene, Johns 

 Hopkins University, Baltimore, Md.] 



In June, 1919, Huldschinsky 1 reported that the ultraviolet 

 ray exerted a curative action in rickets. The criterion on which he 

 relied was the evidences furnished by the X-ray of calcium deposi- 

 tion at the ends of the long bones. He found that there were 

 definite signs of calcium deposition after four weeks of treatment 

 and that at the end of eight weeks healing was almost complete. 

 In May, 1920, Huldschinsky 2 again reported the curative effects 

 of treatment with the ultraviolet ray in rickets in a series of thirty 

 children, aged between one and one half and six and one half 

 years, who exhibited all clinical manifestations of the disease. In 

 all, healing was accomplished after twenty-two to twenty-six 

 treatments covering a period of two months. In April, 1920, 

 Putzig 3 corroborated the findings of Huldschinsky. He obtained 



1 Huldschinsky, K., Deutsch. Wchnschr., 1919. xlv, 712. 



2 Huldschinsky, K., Ztschr. f. orthop. Chir., 1920, lxxxix, 426. 



3 Putzig, H., Therap. Holbmonatschr., 1920, viii, 234. 



