Note the branching filaments--"pseudomycelium" (a). Here and there filaments are broken up at their ends into oval or rod-shaped segments, "oïdia," and behave as spores. Note the asexual reproduction. From the pseudomycelium arise true hyphæ (b), each of which in turn ends in a chain of spores (c). ~MORPHOLOGY OF THE BLASTOMYCETES.~ The blastomycetes are composed of spherical or oval cells (8 to 9.5µ in diameter), which, when rapidly multiplying by budding, may form a spurious mycelium. A thin cell-wall encloses the granular protoplasm, in which vacuoles and sometimes a nucleus may be noted. This latter is best seen when stained with hæmatoxylin (see page 105). During their growth and multiplication the blastomycetes split up solutions containing sugar into alcohol and CO_{2}. ~Saccharomyces~ (Fig. 81).--Note the round or oval cells of granular protoplasm (a) containing solid particles and vacuoles (c), and surrounded by a definite envelope. ~Reproduction.~--Budding; ascospores--asexual. Note the asexual _reproduction_. 1. "Gemmation"--that is, the budding out of daughter cells (b) from various parts of the gradually enlarging mother cell. These are eventually cast off and in turn become mother cells and form fresh groups of buds. [Illustration: FIG. 81.--Saccharomyces with ascospores.] [Illustration: FIG. 82.--Torula.] 2. Spore formation--"ascospores" (e). These are formed at definite temperatures and within well-defined periods; e. g., Saccharomyces cerevisiæ, thirty hours at 25° to 37°C., or ten days at 12°C. ~Torulæ~ (Fig. 82).--Torulæ, whilst resembling yeasts in almost every other respect, never form endo-spores. Note the elongated, sausage-shaped cells (a) the larger oval cells (b) and the globular cells (c) the former two often interlacing and growing as a film. Note the absence of ascospore formation. IX. SCHIZOMYCETES. ~Classification and Morphology.~--Bacteria are often classified, in general terms, according to their life functions, into-- _Saprogenic_, or putrefactive bacteria; _Zymogenic_, or fermentative bacteria; _Pathogenic_, or disease-producing bacteria; or according to their food requirements into-- _Prototrophic_, requiring no organic food (e. g., nitrifying bacteria); _Metatrophic_, requiring organic food (e. g., saprophytes and facultative parasites); _Paratrophic_, requiring living food (obligate parasites); or according to their metabolic products into-- _Chromogenic_, or pigment-producing bacteria; _Photogenic_, or light-producing bacteria; _Aerogenic_, or gas-producing bacteria; and so on. Such broad groupings as these have, however, but little practical value when applied to the systematic study of the fission fungi. On the other hand, no really scientific classification of the schizomycetes has yet been drawn up, and the varying morphological appearances of the members of the family are still utilised as a basis for classification, as under--