Il5 HODGE. [Vol. VII. 



speedily coagulated and holds the ganglia firmly to each other 

 and to the slip. The rule of always placing the stimulated 

 ganglion nearest the end of the slip aids in simplifying matters. 

 Any desired record may be written upon the other end of the 

 slip and all the trouble of keeping a number of little indistin- 

 guishable things from becoming mixed up is at once done away 

 with. The cards are, of course, embedded with the ganglia 

 attached. They can easily be removed, if desired, for cutting ; 

 but I generally place the specimens so that the plane of 

 cutting shall be parallel to the card. In cutting, it has been 

 my practice to give the face of the paraffin block the shape 

 of a trapezoid, with the stimulated ganglion always toward the 

 shorter side. Each section then carries a record of the arrange- 

 ment of specimens within it, and any number of sections may 

 be cut and stored, with no danger of confusion. Not only one, 

 but several pairs can be fastened to the same shps arranged 

 in a row so that they may all be cut at the same time. For 

 example, it was my practice to stimulate the right brachial and 

 sciatic plexuses of a frog : this places at our disposal five pairs 

 of ganglia ; each pair may be hardened in a different way, and 

 all be arranged as described above on a single slip. They are 

 all cut together, fixed to the slide (by alcohol fixative method), 

 and all stained together. Many slides are obtainable from one 

 such set of ganglia, and each slide may be stained in a different 

 way. Thus, incidentally, a permutation of hardening and stain- 

 ing combinations has been obtained which might form the 

 basis of a separate study. 



Not only, in this way, may a dozen specimens be manipulated 

 as easily as one, but they are held in the desired positions rela- 

 tive to each other, and, of special importance, they are cut 

 together. However perfect the microtome, sections do not 

 always come from it of absolutely uniform thickness ; and where 

 minute, or even gross, differences of granulation or staining are 

 to be studied, this is of prime importance. 



The essential feature, then, of my method is that it compares 

 correspotiding ganglia of the same animal -which have been sub- 

 jected to identical treatment in passing from the animal to the 

 slide, t/ie only point of differe^ice being that one has had its nerve 

 stimulated for a longer or shorter time, while the other has not. 

 Methods of hardening and staining do not concern us so long as 



