Spiral Stricture of Muscle. 89 



as it were, into ' etages ' or series. (See fig. 12, where one of these 

 ' etages,' the lowest, is separated from the rest by the cutting 

 of the spirals at their points of crossing.) The dark places in 

 the transverse strise correspond to those separating Bowanan's 

 discs. They are nothing else than the crossing places of the 

 spiral threads. Here the latter come into immediate contact with 

 one another, — can with pressure be made to exercise a cutting 

 power, — and, as before said, actually to cut each other through. 

 This, too, must take place more or less in stories or ' etages,' as 

 the points of crossing are for the most part on the same level. 

 And when the cutting through has taken place, each story or 

 ' etage' represents one of Bowman's discs*. (The author here 

 points out a difference between merely perspective crossing of 

 the spirals, and that crossing where they are in contact ; it being 

 of course at the latter only that there can be a cutting through.) 



Whence comes it that, as was observed by Bowman, contrac- 

 tion at any part of the primitive fasciculus (characterized as this 

 is by greater nearness of the transverse strise) is attended, both 

 before and behind that part, in the longitudinal direction, with 

 a separation of the transverse strise ? The cause, according to 

 the author, is simply this : when the spiral threads extend more 

 in a transverse direction at one part than at another, this can 

 take place in no other way than at the expense in the longitu- 

 dinal direction of their continuations, the winds or loops of 

 which, thereby drawn out of the transverse direction, assume one 

 that is more longitudinal. 



Bowman is right in maintaining that contraction of the primi- 

 tive fasciculus has nothing to do with zigzag inflexions of the 

 same. On the contrary, as Bowman remarks, it has been shown 

 by Owen that it is in relaxation that these zigzag inflexions may 

 arise ; and not only so, but that in the Filaria they are regularly 

 present in relaxation, being there indeed characteristic of the 

 relaxed state of muscle. The author inquires. How then does it 

 happen that such zigzag inflexions may arise in relaxation ? He 

 thinks it may possibly be in the following manner : — Suppose 

 the extreme ends of the primitive fasciculus through any hin- 

 derance to remain fixed, and that the fibrillar, after cessation of the 

 influence of the contractile force, strive by means of their ovm 

 elasticity, and in consequence of the relaxation of their spiral 



* This, however, is not always the case; for at (hfl'erent parts in the 

 breadth of the same i)rimitive fasciculus the fibrils may be in dift'erent de- 

 grees of contraction, and their points of crossing therefore on different 

 levels. In such states the transverse striie, viewed with changes of focal 

 distance, are seen to change their jd.icc continually, according as viewed 

 near the jjeriphery or at greater depth, as was observed by Bowman, and 

 as every experienced microscopic observer must have noticed. 



