EBYSIPHE 01DIUM. 133 



membrane smooth, or closely covered with acicular 

 cjstals of oxalate of lime (fig. 19). . Longish spores 

 (0*008 mm. long, 0'0037 mm. broad). Very widely 

 distributed on all sorts of nitrogenous substances. 

 Mucor racemosus, much more delicate fruit hyphse, at 

 most 1*5 cm. long ; sporangia yellowish to light brown ; 

 spores roundish. Grows extensively on substances rich 

 in carbo-hydrates. When the mycelium is old, or when 

 the spores germinate under water, so-called gemmae or 

 brood cells (that is to say, pear-shaped swollen spots, 

 which develop thick membranes and a protoplasm rich 

 in oil) are formed in the hyphae. On continued culti- 

 vation in saccharine fluids the germinating tubes become 

 constantly shorter, and show yeast-like budding ; the 

 spherical segments are termed spherical or segmentation 

 yeast (Kugel- or Gliederhefe). These spherical yeast 

 cells readily lead to deficiency of oxygen in the nutritive 

 medium, and can then break up any sugar which is 

 present into alcohol and carbonic acid in other words, 

 set up fermentation. The rising bubbles of carbonic 

 acid usually however carry the yeast cells to the surface, 

 where they again form normal mycelium, so that the 

 setting up of fermentation, and the production of C0 2 , 

 seem to be the means by which the fungus returns to its 

 normal conditions of life. 



Mucor stolonifer. Mycelium, with branches rising in arches 

 and again sinking, and attached by root hairs; sporangia 

 deep black and warty ; spores brownish, almost spherical, 

 10 20 mikrom. in diameter ; zygospores dark brown. 



Further : M. macrocarpus ; M. fusiger ; M. aspergillus ; M. 

 phycomyces, rare. 



M. Melittoplitorus. Found in the stomach of bees ; colour- 

 less hyphas, with egg or pear-shaped sporangia ; colourless 

 elliptical spores. 



Lichtheim has recently discovered two new species of Pathogenic 



, . , . species of 



mucor which exert a pathogenic action : mucor. 



M. rkizopodi/ormis. Mycelium at first snow-white, 

 then mousy grey; mycelial threads colourless; 

 brownish mycelial branches rise and sink in an arched 

 manner on the surface of the substratum, giving rise at 

 the point of contact to short branched rhizoids, with 



