546 DEVELOPMENT OF THE SIMPLE TISSUES, BY S. STRICKER. 



chief substance alone, but was absent in the intermediate 

 substance. 



In regard to the internal arrangement of the fibrils, Rollett 

 accepted the views of Leydig, chiefly resting on the examina- 

 tion of transverse sections of firmly frozen ox hearts, according 

 to which the primitive fasciculus is traversed by a lacunar sys- 

 tem. He admitted this in consequence of the configuration of 

 the areas which he obtained from transverse sections. On 

 subjecting the sections to maceration for several days, they 

 were found to present the transverse sections of the fibrils. 

 Cohnheim* subsequently examined muscular fibres methodically 

 by the freezing method, and showed that the transverse sec- 

 tions of such fibres may be regarded as transverse sections 

 through the living tissues. From such sections he has found 

 the proper muscular substance to be composed of two quite 

 different substances, one of which is of great transparency, and 

 possesses a strong lustre, whilst the other is less transparent, 

 and has a dull appearance, the relative quantity of the two 

 being unequal. The highly refractile substance he describes 

 as forming a dense trellis-work of slender lines, becoming wider 

 at certain points only, and decussating at all angles ; the dull 

 substance, on the contrary, being arranged in the form of a 

 mosaic, with innumerable triangles, quadrangles, and pentagons, 

 separated from one another by the slender bands of more 

 transparent substance. At certain points the particles of the 

 mosaic are separated to a greater distance from each other 

 than elsewhere, owing to the accumulation of the refractile 

 substance ; in the middle of these spots are the nuclei of the 

 muscle. Cohnheim regarded the dull areas of the mosaic as 

 the sections of the sarcous elements. He further maintained 

 that the transverse section of the living muscular fibre so far 

 corresponded to the longitudinal view, that in it also the sarcous 

 elements make their appearance, surrounded and enclosed by 

 another substance of a different nature. In regard to the con- 

 sistence of the latter, Cohnheim states, upon the authority of 

 Kiihne's researches, that it must be fluid. 



From this account an essentially novel view of muscular 



* Virchow's Archiv, Band xxxiv. 



