134 NON- PATHOGENIC MICRO-ORGANISMS. 



non-sexual ways. In the former case, certain cells called 

 gametes are set apart, and by 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. Sometimes there is a more 

 definite male element, the antherozoid, and a female ele- 

 ment, 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 sporangia, the protoplasm of which, without being re- 

 inforced from that of another cell, proceeds to break up into 

 the elements of new individuals often called, when motile, 

 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 most extreme species of the group, 

 it does not appear at all and only asexual reproduction 

 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. 



Mucorinae : 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. 44 A 4). One of the fila- 

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

 globular swelling (the sporangium) appears. This sporan- 

 gium 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 



