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 hyphe; 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, b); in 5 we see 
the conjugation which has taken place between two 
dissimilar cells: the male cell, smaller in size 
(antheridvwm) 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 horses, dogs, and 
rabbits. When examined under the microscope, the 
