16 ON THE MINUTE STRUCTURE OF 
the observation made in 1849 by Reichert, a German histologist, that dilute 
nitric or muriatic acid loosens the cohesion of the fibre-cells, and enables them 
to be isolated with much greater facility. In 1852 I wrote a paper ‘On the 
Contractile Tissue of the Iris’, published in the Microscopical Journal, in which 
I gave an account of the involuntary muscular fibre contained in that organ 
in man and some of the lower animals, stating that the appearances I had 
met with corresponded exactly with Kolliker’s descriptions, and illustrating 
my remarks with careful sketches of several fibre-cells from the human iris, 
isolated by tearing a portion of the sphincter pupillae with needles in a drop 
of water. In 1853, another paper by myself appeared in the same journal, 
‘On the Contractile Muscular Tissue of the Skin,’ confirming Kolliker’s recent 
discovery of the ‘arrectores pilt’, and describing the distribution of those little 
bundles of unstriped muscle in the scalp. These and other investigations into 
the involuntary muscular tissue convinced me of the correctness of K6lliker’s 
observations, and led me to regard his discovery as one of the most beautiful 
ever made in anatomy; and this is now, I believe, the general opinion of 
histologists. 
Still, however, there are those who are not yet satisfied upon this subject. 
In Miiller’s Archives for 1854, is a paper by Dr. J. F. Mazonn of Kiew, in 
which the author expresses his belief that the muscular fibre-cells of Kolker 
are created by the tearing of the tissue in preparing it, and denies the existence 
of nuclei in unstriped muscle altogether; but he gives so very obscure an 
account of his own ideas respecting the tissue, that his objections seem to me 
to carry very little weight, more especially as the appearances which he describes 
require, according to his own account, several days’ maceration of the muscle 
in acid for their development. In June of the present year (1856), Professor 
Ellis of University College, London, communicated to the Royal Society of 
London a paper entitled ‘ Researches into the Nature of Involuntary Muscular 
Fibre’. In the abstract given in the Proceedings of the Society, recently 
issued, we are informed that, ‘having been unable to confirm the statements 
of Professor Kolliker respecting the cell-structure of the involuntary muscular 
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.’ In the ‘summary of the conclusions which 
the author has arrived at’, we find the following: ‘In both kinds of muscles, 
voluntary and involuntary, the fibres are long, slender, rounded cords of uniform 
width... . In neither voluntary nor involuntary muscle is the fibre of the 
nature of a cell, but in both is composed of minute threads or fibrils. Its surface- 
