296 GENERAL THERAPEUTICS FOR VETERINARIANS 



For economical reasons, a change of climate for therapeutic purposes is per- 

 missible with the domestic animals only in very rare cases (removal to ele- 

 vated pastures or to distant farms), although frequently such a change ap- 

 pears to be indicated, especially in convalescence. 



Light. — The use of light as a heaUng remedy was introduced by Finsen 

 of Copenhagen. He uses the bactericidal (chemical action of the ultraviolet, 

 violet and blue rays) as well as the inflammation-producing (thermal action 

 of the red rays) forces of light and has in this manner cured numerous cases 

 of lupus in man. His method consists in concentrating the rays of a very 

 strong arc light by means of a rock crystal and directing them through a 

 layer of distilled water which is continually cooled. Iwanow (Repert. d. pol. 

 Sanit. v6t., 1902) has obtained excellent results with Finsen's apparatus in the 

 treatment of eczemas of the horse. 



Rontgen's Rays. — These are used in surgery for the local treatment of 

 malignant neoplasms (carcinomas, sarcomas). Radium acts in a similar 

 manner (radiotherapy). In internal medicine, the Rontgen rays have proven 

 less satisfactory (employed in chronic myelomas and in lymphatic leukaemia 

 and aleukaemic splenic tumors). 



