Excerpt from On the Relations of Micro-Organisms to Disease: The Cartwright Lectures, Delivered Before the Alumni Association of the College of Physicians and Surgeons, New York, February 19, 21, 24 and 27, 1883 Fungi - plants which, because devoid of chlorophyll and therefore unable to fabricate the necessary hydro carbons, are usually parasitic upon animal or vegetable tissues, living or dea d - may be divided into three general Classes: 1, the mould fungi (aspergillus varieties, for example), 2, the budding fungi (e. G. The yeast plant); and, 3, bacteria, or dividing fungi. Bacteria were defined in 1875 by Cohn as cells de void Of chlorophyll, of spherical, Oblong, or cylindrical, sometimes twisted or sinuous form, which reproduce themselves exclusively by transverse division and live either isolated or in families. This definition requires to-day but one modification; reproduction, namely, is known to occur in several species, at least by the forma tion and liberation of sp'ores as well as by fission. The bacteria consist of anitrogenous, highly refractive, usually colorless substance, protoplasm or mycoprotein (n enck1) imbedded In which glistening, Oily looking granules can sometimes be Observed. The bacterium exhibits a power Of resistance toward acids and alkalies which could not be possessed by a nitrogenous substance hence it was assumed by Cohn that the external layer is a Sheath of cellulose or similar hydrocarbonaceous material, such as the mould-fungi are known to possess. Although there has been as yet no decisive ocular demonstration Of the existence of this membrane, the reactions of certain spe cies toward straining fluids corroborate the assumption. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.