30 MICROBES, FERMENTS, AND MOULDS. 



Fig. 15 represents the reproductive organs of 

 Mucor mucedo. 1 is the sporangium filled with 

 ordinary spores ; in 2, the wall of the sporangium 

 has disappeared, so as to show the free spores round 

 the central columella ; 3 and 4 represent the germina- 

 tion of these spores, giving forth their hyphae ; 5 gives 

 the conjugation of the sexual spores, which are fused 

 into one large oospore, 6 ; of this we see the germina- 

 tion in 7, and it produces a hypha terminating in a 

 sporangium. 



Fig. 16 represents the same organs in a Perono- 

 spora. In 1 we see the mycelium of the fungus 

 penetrating the tissue of the infected plant; in 2, 

 the fructifying apparatus containing the ordinary 

 spores issues through a stoma, ramifies, and produces 

 sporangia at the extremity of each branch ; in 3 and 

 4 we see two spores which have issued from these 

 sporangia germinating and penetrating the epidermis 

 of a leaf through the stomata (a, 6) ; in 5 we see 

 the conjugation which has taken place between two 

 dissimilar cells: the male cell, smaller in size 

 (anther idium) is applied to the large female cells 

 (oogonium'), and after this mode of fertilization it 

 is termed an oospore, which is represented in 6. 



Mucor mucedo, and other species of the same 

 genus, form the small downy tufts of a greyish white 

 colour which may be observed on mouldy bread, rotten 

 fruits, and on the excrement of hors.es, dogs, and 

 rabbits. When examined under the microscope, the 



