188 THE MICROSCOPE. 



state, and kills it : others destroy house-flies, which may be 

 seen in the autumn glued by these parasites to the window, 

 on which they have alighted in a semi-torpid state. 



Mother of vinegar (mater aceti) is a mould-plant which 

 is developed in vinegar, and forms therein a thick leather- 

 like coat, similar to the inflammatory crust which covers 

 the crassarnentum of blood drawn from rheumatic patients. 

 It is produced not merely in but from the vinegar, and as 

 it forms the acetic acid diminishes, until ultimately water 

 alone remains. 



This mould-plant belongs to the genus mycoderma of 

 Persoon, or hygrocrocis of Agardh. It is one of the simplest 

 vegetable formations, and belongs to the Fungi rather than 

 to the Algae. It is formed in vinegar obtained both from 

 wine and beer, but not in that procured from wood. It 

 exists in unmixed vinegar, and also in vinegar in which 

 organic substances are preserved. These substances, how- 

 ever, contribute nothing towards the development of the 

 plant, but merely promote the production of a germ or a cell 

 from which the mould-plant is formed out of the elements 

 of the acetic acid. In all cases, whether organic substances 

 be or be not contained in the vinegar, the mycoderma has 

 the same conformation and chemical composition. 



Mulder analyzed three plants formed in vinegars con- 

 taining different vegetable substances. His results gave 

 as the formula for the plant, CISG Hn 5 Ns 96 . The quan- 

 tity of nitrogen contained in protein, is taken as the basis 

 of the formula. By potash all the protein may be re- 

 moved, and the residue is pure cellulose. The latter, 

 according to Payen's analysis, and corroborated by experi- 

 ment, has for its formula, 24 Ebi O^. 1 



Mycoderma aceti, or mother of vinegar, consists, there- 

 fore, of protein and cellular tissue. 



Animals, birds, insects, and fishes, alike suffer from the 

 ravages of fungi. One of the most prevalent observed 

 among our domestic pets is that found growing over the 

 upper surface of the gold-fish ; death is almost certain 

 when this white fungoid disease once commences its 

 ravages upon them. 



(1) Well manufactured paper is nearly, or wholly, composed of cellulose, and 

 may be regarded as the microscopical standard of the cellulose contained in all 

 vegetable tissues. 



