The nervous system in the Cestode Moniezia expansa. 365 



ferentiate nerve tissues from the other tissues as well as Vom Rath's 

 method. 



Throughout the most of my work material was used that had 

 been subjected to sodium chloride solutions, but finally the solution 

 described on page 363 was tried and gave good results. Unfortunately 

 the opportunity was wanting for continuing the work with this more 

 favorable material. The method which at the last was found best 

 adapted to Monieda was as follows: The material collected at the 

 abattoir was placed in the solution the formula for which is given on 

 page 363, and was thus carried to the laboratory. It was there 

 washed and the worms not required at once were placed in the culture 

 solution described above (page 364). Those which were to be treated 

 immediately were cut into pieces consisting of two or three pro- 

 glottides each, dried for a moment on filter paper, and placed in a 

 clean watch glass. The pieces were then covered with a freshly made 

 mixture composed of 60 and 40 volumes respectively of the following 

 solutions, A and B: 



A. methylen-blue (dry) . 1 g 

 hydrant water . . . 1000 ccm 



B. egg albumen (fresh) . 60 g 

 hydrant water ... 40 ccm 



Only enough of this mixture was used to cover the specimens, a little 

 being added from time to time to replace that lost by evaporation. 

 It seemed best to keep the specimens exposed to the air and at a 

 rather low temperature (3 *^ C to 8 " C). After being stained from half 

 an hour to two hours, according to conditions, the material was placed 

 for 20 or 30 minutes in the following freshly made mixture: 

 ammonium molybdate . . 10 ccm 

 hydrogen peroxide ... 2 ccm 

 hydrochloric acid (strong) . 6 drops 

 The object in the use of this mixture was to fix the stain in the 

 nervous tissues and to wash it out of all others ; but its action in the 

 present case shows that this result does not always follow. The 

 tissues were removed from the mixture as soon as they became 

 greenish, the washing out having by that time gone far enough. This 

 took on an average about half an hour, but the time varied with dif- 

 ferent specimens. It was best to keep the mixture containing the 

 objects at a low temperature, near 0° C. This solution was then 

 gradually replaced by adding slowly a 1 7o solution of osmic acid until 

 the ammonium molybdate solution was replaced by a 1 7o solution of 



