256 CHEMOTHERAPY 



the feeling of a solid tumor but rather that of a fluctuating cyst in which 

 small movable tumor particles can be discovered. After the fifth in- 

 jection on the seventh day, this soft mass becomes smaller, the capsule 

 becomes lax, and the configuration of a circumscribed tumor can no longer 

 be distinguished, but only a long edematous cord can be felt. Usually 

 as a result of the sixth injection, in favorable cases, the absorption and 

 diminution proceed so that one gets the feeling of an empty sac. In case 

 no intercurrent disease occurs, the animal is cured in about 10 days, with 

 a disappearance of all remnants of the tumor." 



The intravenous injection of mice requires experience. The substances 

 Intravenous are injected into the caudal vein. The mouse is put into a special re- 

 Injection tainer and the cover of the trap is closed, leaving the tail alone outside, 

 in Mice. The mouse is fixed firmly by grasping the tip of the tail between the left 

 thumb and index finger and holding the tail fully extended. The caudal 

 vein, which is already somewhat congested by the pressure of the cover of the retainer 

 upon the root of the tail, is made more prominent by gentle exposure to heat in the 

 form of a small electric bulb repeatedly passed over and close to the skin. After a 

 little while the superficial epithelial cells become injured by the heat, so that they 

 can be removed by gentle scraping with a sharp scalpel. This exposes the vein. The 

 successive inoculations should begin at the tip of the tail and gradually approach the 

 root. A very fine needle is essential. If the tip of the tail becomes necrotic, it should 

 be simply cut off. 



The exceedingly instructive observations of v. Wassermann 



Conclusion, are at present mainly of scientific character. It would be 



erroneous at once to extend such application to human 



therapy. Still, one cannot fail to see in this work the promise of greater 



things in the future. The important principle that it is possible to have 



chemical substances pass from the blood vessels and specifically attack 



tumor cells ^has been definitely established; and thus it seems merely a 



question of time before the right step is taken toward the solution of 



one of the greatest of human problems. 



