BY DR. KLEIN. 97 



give off numerous fibres, some of which are medullated. but 

 soon lose the medullary sheath, others nou-medullated. Tln->; 

 last are pale, streaked longitudinally, and have nucleated 

 sheaths. By their abundant ramifications, they form a network 

 of rhomboidal or oblong meshes, having nuclei at their points 

 of junction. This network involves the individual muscular 

 bundles, and is called the intermediary network. Pine ii la- 

 ments, containing granules, spring from it, which penetrate be- 

 tween the muscular cells, and divide dichotomously in this 

 situation, forming by their connection the intra-muscular 

 work. In addition to the fibrils which lie between the fibres, 

 the network contains others, which penetrate the muscle-cells 

 and become connected with the nucleoli of their nuclei, in such 

 a way, however, that the nucleolus is not the end of the fibril, 

 but is intercalated in it. It is only in a few, out of a great 

 many successful preparations, that the intra-muscular network 

 can be demonstrated. Most serve to show only the interme- 

 diary plexus. 



Nerves of the Striped Muscles. The demonstration 

 of the nerves of voluntary muscle has, hitherto, been accom- 

 plished only in fresh preparations; there are, however, one or 

 two cases in which the silver method can be used. It is, in 

 the first place, to be borne in mind that only muscles that are 

 still irritable are of any use for the purpose. Secondly, that 

 the greatest care must be taken in making the preparation, 

 especially to prevent the cover-glass from pressing, by strips 

 of paper. 



Muscular Nerve Endings of the Water-beetle. The 

 muscles of certain invertebrate animals, e. g., Dytiscus, or, still 

 better, Hydrophilus piceus, and particularly those which pass 

 from the thorax to the legs, are best suited for the purpose. 

 The muscle is severed near its insertion with fine, sharp scis- 

 sors, and at once placed on the object-glass and covered, or 

 transferred to a drop of serum and spread out so as to sepa- 

 rate a few muscular fibres. It is easy to recognize the broad, 

 riband-shaped, raedullated nerve fibres, each possessing a stri- 

 ated axis-cylinder, which rapidly divide into finer non-medul- 

 lated fibres, each distinctly streaked and beset with nuclei. A 

 single muscular fibre ma}' receive several non-medu Hated nerve 

 fibres. At the point at which each enters the muscular sub- 

 stance, a more or less marked elevation is distinguishable, the 

 so-called Doyere's prominence. This consists of granular sub- 

 stance in which clear, roundish nuclei are embedded. The 

 prominence, with its nuclei, is lengthened out into processes in 

 directions corresponding with tnat of the axis of the muscular 

 fibre. These processes may either stretch along the surface of 

 the muscular fibre, or sink into its depth. Sometimes the 

 prominence is represented by a mere lamina of granular sub- 

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