1 18 NON-PA THOGENIC MICRO-ORGANISMS. 



the union of two of these the embryonic male and female 

 elements a new cell called a zygospore is formed which 

 after a period of rest grows into a new individual. Some- 

 times there is a more definite male element, the antheridium, 

 and a female element, the oosphere, and the coalescence of 

 these forms an oospore which subsequently behaves like a 

 zygospore. In the non-sexual reproduction there are formed 

 certain cells called brood-cells or gonidia the protoplasm of 

 which, without being reinforced from that of another cell, pro- 

 ceeds to break up into the elements of new individuals often 

 called swarm-spores. Both forms of reproduction are usually 

 manifested by each species. The degradation of the fungi 

 consists in the gradual loss of the faculty of sexual repro- 

 duction, so that, in the lower species of the group, it does 

 not appear at all and only gonidium formation can be traced. 

 We shall now describe a few of the typical forms of these 

 lower fungi which are often met with in bacteriological 

 work. 



Mucorinse : Mucor Mucedo. This form occurs especi- 

 ally in the putrefaction of horse dung and also in other 

 putrefactions. To the naked eye it appears as a white or 

 brownish -white mass of fine filaments, from which, here 

 and there, rise special filaments often several inches long, 

 having at their terminations spherical brown swellings, the 

 reproductive elements. Microscopically, the plant consists 

 of branching non- septate filaments. Such a structure is 

 called a mycelium. The non-sexual is the commonest form 

 of reproduction (vide Fig. 39 A 4). One of the filaments 

 grows out, at its termination a septum forms, and a 

 globular swelling (the brood-cell) appears. This brood-cell 

 possesses a definite membrane. Within it from the septum, 

 grows a club-shaped mass of protoplasm called the 

 columella, to which are attached the swarm-spores formed 

 from the breaking up of the rest of the protoplasm. When 

 ripe the brood-cell bursts, the brown swarm-spores are cast 

 off, and from each a new individual arises. Under certain 

 circumstances sexual reproduction occurs (vide Fig. 39 A 1-3). 

 Two filaments approach each other, and a small piece of 



