PROCEEDINGS OF SOCIETIES. 63 
description given of this substance in a former notice to the 
Society in June last. 
You may remember that this proposition was also con- 
tained in my paper on iodo-strychnia, which was withdrawn 
from the Royal Society by me in June last, in consequence 
of a necessity for revision and the completion of experiments 
requisite to settle the formula of that peculiar substance, and 
the introduction of an abstract of the literature concerning it. 
I remain, &c., 
W. Brrpo HeErapatu. 
June 19th, 1856. 
Lord Wrottesley, President, in the chair. 
“ Researches into the nature of the Involuntary Muscular 
Fibre.’ By Gurorce Viner Ex.is, Esq., Professor of 
Anatomy in University College, London. Communicated 
by Dr. Suarpey, Sec. R.S. 
(Abstract.) 
Havine been unable to confirm the statements of Professor 
Kolliker respecting the cell-structure of the involuntary mus- 
cular fibre, the author was induced to undertake a series of 
researches into the nature of that tissue, by which he has 
been led to entertain views as to its structure in vertebrate 
animals, but more especially in man, which are at variance 
with those now generally received. The present communi- 
cation contains the results of these inquiries, which tend to 
show that the voluntary and involuntary muscles resemble 
each other very closely in the arrangement and constitution 
of their fibres. 
After adverting to the present state of opinion on the sub- 
ject, the author gives an account of his own observations, 
and treats successively of the interweaving of the fibres, their 
size, form, and ultimate structure; their mode of attach- 
ment at their extremities, their length, and the corpuscles 
connected with them. He devotes a section also to the 
question of the periodic formation and destruction of mus- 
cular fibres in the uterus, in its different conditions; and 
while he is led by his own investigations to recognise an en- 
largement in size of the individual fibres of that organ during 
pregnancy, followed by subsequent diminution, he is unable 
to confirm the doctrme of new formation. Moreover, he 
finds that durmg pregnancy a considerable amount of granu- 
lar matter, with round or oval granular-cells, is deposited 
among the fibres. He adduces reasons for believing that 
