Mode of Contraction of Voluntary Muscular Fibre. Ill 



pu apercevoir dans ces fils une marche vraiment ondee, et il m'a 

 paru que les petites taches curvilignes du faisceau primitif etoient 

 ibrmees par les petits signes, ou diaphragmes, des fils charnus 

 primitifs/' (PL VII. fig. 3.) 



Sir Everard Home and Mr. Bauer took up the microscopical 

 investigation of muscular fibre in 1818 and again in 1826. Un- 

 fortunately for science they fell into remarkable errors. Their 

 observations retarded rather than advanced the microscopic ana- 

 tomy of muscle, and raised doubts as to the credibility of any 

 conclusions drawn from microscopic observations. 



Sir Everard Home and Mr. Bauer *j seeing the tendency which 

 blood- corpuscles have to unite in a longitudinal series, fancied it 

 highly probable that the fibrillse of striated muscle were formed 

 in the same manner. Sir Everard states that the particles of the 

 fibrillse are of the same diameter as the blood-corpuscles deprived 

 of their colour ; he supposes Leuwenhoek^s assertion, that muscle 

 is composed of globules of less diameter than the blood- corpuscles, 

 incorrect, and he endeavours to account for this supposed mistake 

 by adducing the fact, that Leuwenhoek never possessed a micro- 

 meter. 



Mr. Skey, in a paper in the ' Philosophical Transactions,' sets 

 forth as his opinion, that each muscular fibre is a tube, contain- 

 ing in its interior a semi-transparent amorphous substance ; the 

 tube he supposes to be composed of fibrillse, and the transverse 

 striae to be depressions on the surface of the fibre. 



The views of Miiller, Schwann, Lauth and Henle are very 

 similar to those advanced by Fontana. 



Schwann considers the fibrillse to be beaded filaments, pre- 

 senting under the microscope a succession of dark points sepa- 

 rated by light and somewhat narrower portions of the fibril. 



Dr. Martin Barry holds the structure of muscle to be spiral ; 

 he says each fibril is composed of two spirals coiling in opposite 

 directions. 



From these observers I shall pass to those who in recent times 

 have examined the fibrillse of muscle, with a view to determining 

 the real constitution of these filaments. 



The publication of Mr. Bowman's paper in the ' Philosophical 

 Transactions ' was an sera in the microscopy of muscle, though he 

 does not seem to have been able to make out the ultimate con- 

 stitution of the fibrillse, which he considered were composed of a 

 series of highly refracting particles of one kind ; he thus describes 

 them : — 



" Fibrillse present alternate dark and light points when the 



* Philosophical Transactions, 1818 and 1826. 



