354 THE SOLIDS. 



difficulty. Thus, there is no question but that successive crops 

 of corpuscles or nuclei are continually being formed in both 

 the striped and the unstriped muscles, and that those in the 

 former are permanent, whilst in the latter they are only 

 transitory. 



It will be readily perceived that the above detailed views 

 of the structure and development of the muscular fibre differ, 

 in very many important particulars from those generally 

 entertained. According to the views of most physiologists, 

 the unstriped muscular fibre is the analogue of the striped 

 fibre ; while, according to those of the author, the striped 

 fibrilla is the analogue of the unstriped fibrilla, or " fibre " of 

 most writers. Dr. Carpenter, in the third edition of the 

 " Principles of Human Physiology," thus clearly gives ex- 

 pression to the notion that the striped and unstriped muscular 

 fibres are the analogues of each other. " From the pre- 

 ceding history, it appears that there is no difference at an 

 early stage of development between the striated and the non- 

 striated forms of muscular fibre. Both are simple tubes, 

 containing a granular matter, in which no definite arrange- 

 ment can be traced, and presenting enlargements occasioned 

 by the presence of the nuclei. But whilst the striated fibre 

 goes on in its development, until the fibrilla), with their 

 alternation of light and dark spaces are fully produced, the 

 non- striated retains throughout life its original embryonic 

 character." The description just quoted, in its application 

 to thejftbrUke of the striped and unstriped muscle, would be 

 most true, but in its comparison of the unstriped fibrilla? with 

 the entire striped fibre, it is completely at fault. 



There is considerable discrepancy between the views en- 

 tertained by Bowman and Valentin, and those expressed in 

 this work, in relation to the development of muscle, as will be 

 evident from the statement of them by the former gentle- 

 man. " The researches of Valentin and Schwann have 

 shown that a muscle consists, in the earliest stage, of a 

 mass of nucleated cells, which first arrange themselves in a 

 linear series, with more or less regularity, and then unite to 

 constitute the elementary fibres. As this process of the 



