1892.] THE MICEOSCOPE. 205 



to result from the manner in which the granules may be separated, 

 either longitudinally or transverseh'. A number of granules de- 

 tached lengthwise form a fibril, while transverse division forms 

 discs. The opinions of other eminent histologists regarding 

 muscular structure were given, when the doctor came to speak 

 of his own observations and conclusions. While he had con- 

 firmed the opinions and observations of others on this subject, he 

 had found, particularly in crab muscle treated with alcohol, a 

 still more distinctly duplex structure. By teasing with fine 

 needles the fibres are seen to be largely made up of longitudinal 

 fibrils, each of which forms a chain of muscle prisms or elongated 

 sarcous elements, linked together by narrow grooves. Stretch- 

 ing with the needles in many cases makes the grooves to dis- 

 appear and the fibril to assume the form of a cylindrical rod, 

 often tapering at the end. In addition to these longitudinal 

 fibrils, teasing with the needles demonstrates the intervening sub- 

 stance to be also fibrillae, but generally smaller in diameter, and 

 arranged in spiral form around the others. The intermediate 

 fibrils pass between the longitudinal ones, and after twisting 

 around them so as to form a groove in each rod, they bend up- 

 ward again to the next groove, and so on to the end of the fibril. 

 Contiguous grooves in the longitudinal fibrils produce the discoid 

 marks or divisions. 



In teasing, the needle sometimes breaks oft' one of the slender 

 fibrils at the place where it binds the sarcous filaments, or just 

 beyond it, when it appears as a broken thread. At other times 

 the needle separates the filaments from all its grooves, showing 

 the spiral weaving, or it may appear as crossing from fibril to 

 fibril, in a ladder-like form. In the study of these spiral weav- 

 ings the doctor found it necessary to bear in mind that the fibrils 

 are all semi-solid and glutinous, and liable to vary in appearance, 

 according to the tension, or from variations in the original struc- 

 ture. 



I have not found it practicable to demonstrate the spiral plait- 

 ing in every piece of muscular fibre examined. In some speci- 

 mens the glutinous muscle substance had been so hardened by 

 the reagent that teasing with needles could not unravel nor 

 even separate the fibrils. In such instances the fibres showed 

 the striae in the usual way ; but softer and more flexible fibres 

 are readily separated into fibrils which, when stretched with the 

 needles, are more or less unraveled. 



A small piece of teased fibre may be stained and mounted in 

 glycerine. The end portions of the specimen will probably ex- 

 hibit unmarked longitudinal fibrils. Sometimes these show the 

 grooved markings, producing a prismatic or bead-like structure. 

 Where the needles have not been used, the transverse markings 

 and short fibrils, like Bowman's sarcous elements, will be seen ; 



