360 WM. L. TOWER, 



results obtained by many authors in using the chrome-osmium-silver 

 method of Golgi and the melhylen-blue method in neurological studies 

 on other animals, and the interesting character of these worms, it is 

 rather surprising that the condition of the nervous system should 

 have been incompletely determined. Some explanation of this may 

 be found, however, in the seemingly indifferent action of the chrome- 

 osmium-silver method upon Invertebrates in general ; in the transient 

 character of methylen-blue impregnations; in the loose arrangement, 

 the non-raedullated character, and the small size of the nerve fibres 

 of Cestodes, which render ordinary stains useless; and in the con- 

 sequently almost total failure of the best nerve methods when applied 

 to these parasites. All these conditions combine to make the study 

 of the nervous system in Cestodes very difficult. 



From the time of Niemiec's (1885) paper until that of Bloch- 

 MANN (1895) little or nothing had been discovered on this subject. 

 Previous to the appearance of Blochmann's paper the nervous system 

 of the Taenias had been known to consist of a system of ganglia, 

 commissures, and connectives in the scolex, more or less complex, 

 according to the species, as described by Niemiec (1885); one large 

 and one or two accessory lateral nerve trunks, lying external to the 

 longitudinal excretory tube; and two dorsal and two ventral nerves 

 that could not be traced beyond the neck region. Occasional branch- 

 ings of these nerves in the proglottides had been recorded by various 

 authors, but the course of these branches, and the existence of ganglionic 

 cells had not been clearly demonstrated in any form until within the 

 past two years. The papers of Blochmann, Zernecke, LtJHE and 

 CoHN, a note by Köhler and one by myself all confirm the existence 

 of a constant, definite and extensive system of ganglia, commissures, 

 and connectives, a wealth of ganglionic cells, and the existence of 

 nerve terminations in the periphery of the animal that would seem to 

 indicate for them a sensory function. 



These results have been obtained by the use of three methods: 

 that of Golgi, the methylen-blue intra- vitam stain, and the proper 

 use of Vom Rath's fluid. In my work I have been only slightly 

 successful with methylen-blue, and wholly unsuccessful with Golgi's 

 method; but by the careful manipulation of the material in Vom 

 Rath's fluid, followed by crude pyroligneous acid, very desirable results 

 have been obtained. Many other methods have been tried, but without 

 success. 



Another and rather difficult problem constantly confronted me 



