On Contractile Tissues in the Hymenomycetes
Authors: Hoffmann Hermann 
Published: April 2021

ABSTRACT
The annulus on the stipe of Agaricus muscarius is free at the lower margin, hanging down in folds ; above it blends more and more intimately with the outer surface of the stipe, and ultimately can no longer be definitely distinguished from it. The upper side of this frill-like investment of the stipe, or that which is directed towards the angles of the gills, is covered with a delicate loosely-felted tissue, which is, at first, white, but, as the fungus grows, assumes a yellowish tint. This covering is especially well developed, superiorly in the obtuse angle, formed between the projecting annulus and the stipe. If a small portion of the surface of this felted tissue be raised with a fine elastic needle, and placed in a drop of water, care being taken to avoid any strong pressure, whilst the point of the needle is moved about in the water until the particle is detached, it will be observed even under a moderate magnifying power, but very distinctly under one of 363 diam., that the delicate filamentous cells of the structure are furnished with a vast number of gelatinous nodosities, or verrucosities, from which, occasionally, and frequently in numbers together, actively vibrating filaments project. They have the apparent length of to 1 inch, and the thickness of a needle ; but more close investigation soon shows that they vary in length and thickness. The latter reaches, on the mean, 1-450th of a Paris line, varying from 1-800th to to 1-200th. The length is usually about 3-100ths, varying from 1-200th to 7-100ths. A gradual transition may be observed from this filament to immotile, discoid, minute elevations of the gelatinous matrix, and lastly, to simple, verrucose, nodular corpuscles. The movement of these vibratile filaments is very remarkable, and is especially well adapted for microscopical demonstration. It has the closest resemblance to that of the horns of the Snail, but is far more lively ; it resembles also, in some respects, the rowing motion of certain cilia, and the sweeping undulations of the Oscillatoriœ, or even an infundibuliform movement will be observed to predominate. Irritation of the filaments is succeeded by a violent convulsive movement, followed by a depression of the extremities ; sometimes by a spiral involution of the upper portion towards the lower ; lastly, and most frequently, a rapid retraction of the filament into itself may be noticed, exactly as in the horns of the Snail. Spontaneous and perfect retraction, without any external cause, I have never observed. It is extremely rare that this movement alternates with a remission, or actual brief repose ; it is independent of the time of day, or the age of the fungus; and it continues for a long time after the separation of the shred from the parent stem. If the preparation be placed in a little glass cell, closed so as to prevent evaporation, and brought under the microscope, distinct, though very faint, movements may be perceived, even at the end of 48 hours ; ultimately, the substance is affected by the water in which it is macerated, the filaments shorten, and, at last, their remains, together with the gelatinous nodosities, appear to become distended into vesicles with large vacuities in the interior.