PBOTOPHYTIC AND OTHEK FUNGI. 30T 



CHAPTER VII. 

 PROTOPHYTIC AND OTHER FUNGI. LICHENS. 



302. Ix the lowest forms of the group of Fungi, we return to the 

 simplest type of Vegetation the single cell; and such forms, equally 

 with the lowest Algw, rank as Protophytes. Their essential difference 

 from the Protophytic Alga3 seems to lie in their incapacity for the for- 

 mation of Chlorophyll and of carbon-compounds, under the influence of 

 Light, out of the simple binary compounds Water, Carbonic Acid, and 

 Ammonia supplied by the Inorganic world; and in their dependence 

 (like Animals, g 220) upon those more complex combinations which the 

 Organic world alone supplies. There seems, however, to be this general 

 difference between the nutrition of Fungi and that of ordinary Ani- 

 mals: that the former not only live, but thrive best, in the midst of 

 decomposing or decomposable Organic matter, apparently utilizing the 

 products of such decomposition; whilst the latter directly convert into 

 their own substance the nitrogenous compounds prepared for them by 

 Plants. There are, however, cases in which this distinction, also, seems 

 to fail; and in which it is impossible, in the present state of our knowledge, 

 to draw a definite line of division between Fungi and Protozoa ( 322). 



303. Among the Protophytic Fungi, there are none of which the 

 study is more practically important, than the group of Schizomycetes; 

 consisting of a series of very minute organisms, known as Bacteria, Vi- 

 briones, etc., which were formerly ranked by Ehrenberg and Dujardin 

 among Animalcules. They are all aquatic in their habit, and are in that 

 respect allied to A lg&; but they cannot live in pure water, thriving best 

 in liquids that contain decomposing or decomposable organic matter; 

 whilst many of them also grow and reproduce themselves in solutions in 

 which ammonia-salts of the vegetable acids (acetates, tartrates, or citrates) 

 are combined with purely inorganic ash-salts, so that they may be ' culti- 

 vated ' in. such liquids for the purposes of study. 1 Thus the Schizomy- 

 cetes resemble ordinary Plants in forming Xitrogenized compounds out 

 of ammonia, which Animals cannot do; while they differ from green 

 Plants in their inability to form Carbon-compounds by the decomposi- 

 tion of carbonic acid, requiring for their support the carbo-hydrates or 

 their derivatives. They all consist of minute cells, which multiply rap- 

 idly by subdivision; and most of them, at some stage of their existence, 

 have the power of moving more or less quickly through the liquid they 

 inhabit, by the action of flagella. Although usually colorless, or nearly 

 so, they sometimes form reddish, bluish, or brownish coloring matters; 



1 Cohn's solution is composed of 1 part of Potassium Phosphate, 1 part of 

 Magnesium Sulphate, 2 parts of Ammonium Tartrate, and 0.1 part of Calcium 

 Chloride, dissolved in 200 parts of distilled water. See also p. 123 note. 



