PROCEEDINGS OF SOCIETIES. 195 



the table are mostly from fruit — oranges and apples — and also from 

 bread. 



Years ago a considerable interest was created by tbe introduction 

 of a new article of domestic economy in the form of a slimy mass of 

 gelatinous matter, very much like inferior boiled tripe, and called the 

 vinegar plant. It was said to have been introduced from India or 

 South America. It was usually placed in a jar containing a solution 

 of treacle or sugar, and, on being allowed to remain in a warm situa- 

 tion for a month or six weeks, the liquid was found converted into 

 vinegar by the action of this strange plant, which also propagated 

 itself by subdivision, for on looking underneath laminae were observ- 

 able, which could be separated, and, when placed in the proper media, 

 would develop into new plants. This curious plant has been un- 

 doubtedly resolved into a Penicillium, the gelatinous mass being only an 

 abnormal condition of the mycelium, due probably to its submerged posi- 

 tion, for when allowed to dry up, the fruit of Penicillium glaucum is in- 

 variably produced. The general mass of the vinegar plant is structure- 

 less, but near the middle are chains of cells of all sizes, many of which 

 are undistinguishable from those of the yeast plant, which fact suggests 

 the idea of a family likeness, an idea now fully established ; and as the 

 yeast plant is a known cause of vinous, so also the vinegar plant seems to 

 be a cause of acetous fermentation, and, as both are but different forms 

 of Penicillium glaucum, so it comes about that the common mould 

 of our bread paste, &c, becomes the presiding genius over the great 

 regenerating work of fermentation, giving us not only our yeast 

 wherewith to make our bread, but also vinegar for our pickles, and, what 

 is better still, " wine, which maketh glad the heart of man," and 

 last — but not least — our " far-famed bitter beer." 



The yeast plant, as you well know, consists of round or oval cells, 

 which live, expand, and give rise to new cells or plants by budding 

 imtil the fermenting principle is exhausted. The cells are round at 

 first, and as the fermenting principle is nearer exhaustion they become 

 oval, then linear and filamentous, advancing to the primary stage 

 of mycelium, until finally they develop themselves into the normal 

 threads and fruits of the common Penicillium glaucum. Berkley says 

 that he and Mr. Hoffman followed up the development of individual 

 yeast globules in fluid surrounded in a closed cell with a ring of air 

 until the proper fruit of Penicillium glaucum was developed. Some 

 years ago the bread of Paris was much infested with Penicillium, the 

 spores of which were found capable of sustaining a heat equal to 

 that of boiling water without destroying their germinating power. 

 The disease known as aptkas or frog, and which is one of our earliest 

 troubles, is now generally believed to be a species of Penicillium, as 

 is also the filamentous growth constant in the tartar of the teeth. 



The last of these common moulds is known as Mucor. It belongs 

 to the family Physomycetes, and order Mucorini, the genus being Mucor, 

 which, as in the case of Aspergillus and Penicillium, a number of species 

 exist. The mycelium consists of delicate branching filaments, forming 

 a beautiful network, which is distinguished from the mycelia of 

 Penicillium and Aspergillus by its consisting of simple tubes, without 



