362 WM. L. TOWER, 



in distorting and often tearing the scolex to such an extent as to 

 render it unfit for use. Each parasitized animal usually contained 

 from two to fifteen worms, each from 50 cm to 200 cm in length, 

 and I have occasionally taken more than fifty (once 58) good-sized 

 worms from one host. 



B. Methods. 



1. Media for Collection and Transportation. 



The worms were quickly separated from the contents of the in- 

 testines by the fingers, not with forceps, and placed in one of several 

 media for transportation to the laboratory. For this purpose physio- 

 logical salt solution (0,75 **/o) was first used. This was tried at various 

 temperatures, from 10^ C to 30** C, but was found to be uniformly 

 harmful, as it produced stupefaction and rapid death, accompanied by 

 a more or less marked plasmolysis. Distilled water, faucet water, 

 and distilled water with sodium chloride in varying percents (1 % to 

 6,5 7o) were in the lower grades accompanied by strong plasmolysis, 

 while the higher percents acted as an irritating stimulant, producing 

 distortions and death. If the material was afterwards to be treated 

 with Vom Rath's mixture, the physiological salt solution gave fair 

 results, provided the worms were placed in his mixture as soon as 

 the laboratory was reached. It was positively harmful, however, to 

 allow the worms to remain in this solution more than one hour; for, 

 even after only an hours exposure. Vom Rath's method was rather 

 ineffective, as far as the demonstration of the nerves was concerned. 

 It would have been more desirable to have placed the worms in the 

 killing fluid at the abattoir; but, as all foreign substances had to be 

 removed before killing, and this could not be done at the abattoir, it 

 was necessary to defer the killing until they had been taken to the 

 laboratory. 



A mixture produced by adding one percent of pepsin to normal 

 salt solution gave better results, as the reaction upon the worms was 

 not as pronounced as that shown by the physiological salt solution. 

 With material collected in this mixture, as also with that in the 

 simple salt solution, I was unable to obtain a satisfactory intra-vitam 

 stain by the methylen-blue method or a satisfactory Golgi impregnation, 

 although methylen-blue was found to stain to some extent. If the 

 amount of sodium chloride was decreased and that of pepsin increased 

 to the following proportions, 



