MOLDS 



43 



membrane, a hyaline nucleoplasm, a large nucleolus and a chromatic 

 network. The last is sometimes indistinct, and it frequently happens 

 that the nucleus appears to contain only a nucleolus; but a very 

 careful examination always reveals the network (Fig. 25, 3 and 4). 



The division of the nucleus is not always easy to observe. To study 

 it, one must examine the growing tips of the mycelium. In some cases 

 this consists in an elongation of the nucleus which soon assumes the 





-. 



FIG. 26. 



FIG. 27. 



FIG. 26. Various molds fixed and stained by a special technic, showing 

 their chondrium. i, Filament of Rhizopus nigricans (Mucor). 2-4, Filaments of 

 Penicillium glaucum, 5 and 6, Fragments of the conidial organ of the same 

 mold. 7, Filament of Endomyces magnusii. 8 and 9, Oidia of the same mold. 

 In all these molds, chondrium is represented by long filaments, or sometimes 

 by small grains. The filaments often show small vesicles at their crossing. 



FIG. 27. Nucleus of the Mucor (1-4), and various stages of its division (5-8). 

 (After Moreau.} 



form of a very slender dumb-bell which breaks apart at the narrow 

 portion. This is the extent of an amitotic or direct division (Fig. 25, 

 2 and 5). 



Karyokinesis is usually seen only in the organs of fructification 

 (asci, basidia, etc.) ; nevertheless, in the mycelium of the Basidiomycetes 

 and Mucorinece, true metamitoses have been found. In the Mucorinea 

 for_example (Fig. 27), the nucleus loses its membrane (1-4) and gives 



