76 TRANSVERSELY STRIPED MUSCULAR FIBRES. 



break up transversely into discs (Bowman*) or into parallelepi- 

 peds, and each separate fibril into smaller linear sections, and, 

 finally, into serially arranged granules (see vol. ii, p. 127). The 

 continuity of the elementary fibres is therefore readily destroyed in 

 the direction of the contractions. On the other hand, the mus- 

 cular fibrils, as I perceived long before I was acquainted with 

 Bowman's observations on the subject, undergo certain alterations 

 of form by which they are either shortened or lengthened, when 

 subjected to the action of water and other substances. I treated 

 the muscular fibres of the extremities of tolerably developed 

 embryos of the common mouse (mus domesticus) with different 

 chemical reagents ; I found that the addition of water had the effect 

 (as Bowman has very often observed) of rendering the striation 

 more indistinct, and sometimes even causing it wholly to dis- 

 appear ; but when very saturated solutions of neutral salts, such as 

 chloride of calcium, sulphate of soda, hydrochlorate of ammonia, 

 or of sugar, &c., were added, the transverse strise which were 

 originally at a relatively great distance from one another, came 

 nearer together, the shortening being readily appreciable by the 

 micrometer. The transverse striae themselves appeared to be 

 sharper and more distinct, but separated again more widely from 

 one another when the saline solution was washed out as much as 

 possible by water ; and although their outlines grew fainter, they 

 could not again be made wholly to disappear. This observation, 

 which was frequently repeated, proves, at all events, that the mus- 

 cular fibrils have a different capacity for imbibition at their 

 varicosities and constrictions, depending upon a difference in the 

 aggregation of their smallest mechanical, if not chemical, particles. 

 The elementary fibre of the animal muscles cannot therefore be 

 considered as homogeneous ; nor can we regard the phenomena 

 which are produced on the application of saline solutions, as 

 the effect of simple contortions of the fibres, such as Henle ob- 

 served in connective tissue. 



If the physical examination of the muscular fibrils shows that 

 they are not simple, homogeneous, partially folded strands, this is 

 still more distinctly proved by a chemical investigation, as it 

 destroys the fibres; for whatever may be the reagent employed, the 

 fibrils are always unequally dissolved. First of all, there are formed 

 small filaments resembling vibriones, which, together with fat- 

 globules, resolve themselves into a number of molecular, often 

 serially arranged granules. If we regard the primitive fibres as not 

 * Philosophical Transactions for 1840, p. 457. 



