490 
MR. BOWMAN ON THE MINUTE STRUCTURE AND 
closely together in the one part, and stretched to a corresponding degree immediately 
beyond. This first stage is represented in fig. 89. 
The nucleus of contraction slowly extends itself, by involving a greater length and 
a greater number of fibrillse, and while doing so, has generally an oscillation along 
the implicated fibrillse, effected by the alternate attraction and partial release of striae 
at its opposite ends. It would almost appear as if the contractile force of the spot 
were limited; able only to engage a certain amount of the mass; so that, as fresh 
portions were assumed on the one hand, some were relinquished on the other. But 
the occasion of the oscillation would seem to be the traction of neighbouring points, 
also active, striving to acquire additional striae ; for, as before observed, the cut extre- 
mities are always the first to contract, and being thereby rendered thicker, are in 
some measure restrained from approaching each other by the mica or glass, with 
which it is necessary to cover the object. Be that as it may, the movements are such 
as to convey the idea of opposing forces struggling for the mastery, and they do not 
cease till the whole fasciculus is contracted to less than half its original length. 
They prove incontestably, that the agency in question, whatever it may be, operates 
primarily on the individual segments of the fibrillse. 
When a contraction is very forcible and going on at the same moment at several 
points of a fasciculus, it may happen, if the pressure on the extremities prevents their 
approximation, that the intermediate flaccid portions are stretched even to laceration, 
as seen in fig. 75. from the Frog. This fact may serve to illustrate those remarkable 
cases of muscular rupture from inordinate action, concerning which much has been 
written*. 
In the Skate, the following appearances once presented themselves. Dark waves 
of contraction, caused by the successive approximation and recession of one side of 
the discs, began to play backwards and forwards along one margin of the fasciculus. 
These gradually included the whole breadth of the fasciculus, and then coalesced ; 
permanent rugee at the same time forming in addition, each about ^woth inch broad, 
and including twenty or thirty of the approximated striae. Fig. 88. exhibits these al- 
terations. 
A contracted fasciculus has often a somewhat uneven or undulated margin, which 
is sometimes occasioned by very slight irregularities or puckerings of the fibrillse, 
but more frequently by a transverse wrinkling of the sarcolemma, which, when this is 
extensively separated by fluid from the fibrillse, is almost a necessary consequence of 
* See J. L. Petit ; and M. Roulin, Majendie’s Journal, vol. i. p. 295. [I have just been indebted to the 
kindness of Mr. Busk, surgeon to the Dreadnought Hospital Ship, for an opportunity of examining specimens 
of muscle, ecchymosed and ruptured by spasmodic action during a rapidly fatal tetanus. We found them to 
present appearances of disintegration, such as are frequently seen in fasciculi inordinately contracted under the 
treatment above described, and this to so great an extent, that in many parts neither transverse nor longitu- 
dinal striaj could be discerned, but only a confused mass of primitive component particles, held together by the 
sarcolemma, as seen in a portion of fig. 37. from the Frog. Other muscles from the same subject, 'which had 
been free from spasm, were in all respects natural. — November, 1840.] 
