. Electro-physiology . of the axis-cylinder, running in opposite directions, within the substance of the expansion. These are for a short distance parallel with the long axis of the muscle-fibre, and then appear to end freely. In other cases they send out a few short side- branches, the presence of which is sometimes indicated only by isolated dark - blue droplets. Finally, the nerve-endings (in consequence of the great in- stability of the intrinsically delicate, naked axis - cylinder) often appear merely as an ac- cumulation of greater and smaller, and no longer coherent, drops (stained blue
. Electro-physiology . of the axis-cylinder, running in opposite directions, within the substance of the expansion. These are for a short distance parallel with the long axis of the muscle-fibre, and then appear to end freely. In other cases they send out a few short side- branches, the presence of which is sometimes indicated only by isolated dark - blue droplets. Finally, the nerve-endings (in consequence of the great in- stability of the intrinsically delicate, naked axis - cylinder) often appear merely as an ac- cumulation of greater and smaller, and no longer coherent, drops (stained blue) within the expan- sion - - their real nature being- apparent only on comparison with other parts of the same preparation. Similar observa- tions have recently been com- municated by Eina Monti (53) upon different insects. Foettinger (53) gives a differ- ent account of the motor nerve- FIG. in a muscle- endings ill illSGCtS, pointing tO a ''"'""' fundamental difference between vertebrates and insects. In the beetles investigated by him (Chri/somela coerulea,Lina tremula, Hi/t!rt>lt //us piceus, Passali'* glaberrimus) there were, as a rule, several, often many, nerve- endings to one primitive fibre, and these—as may be verified on hardened preparations—are frequently (? always) the starting- point of waves of contraction. After treatment with osmic acid and alcohol, delicate fibrils or filaments may sometimes be dis- tinguished in the side-view of a Doyere's expansion; these start from the junction of the ingoing nerve-fibres, and pass to the intermediate discs (Fig. 226). If this be a real irradiation of the axis-cylinder, there must be direct continuity between
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