MUOOBINI. 



239 



to form a mycelium ; that is always the result of the 

 growth of spores from the sporangia. 



(a) In the study of tlie Moulds it is almost always necessary to mako 

 use of alcohol for freeing the specimens of air ; afterward they usually 



Fig. Vb2.—Plptoeephalia Freseniana, parasitic upon the hyphse, Jf, M, M, of Muccn 

 Mucedo. m^mt parasitic hypliae, attached to their host by the haustoria, A; c,conid- 

 ial spores ; s, s, the two brancheswhich conjugate and form the zygospore, Z. Highly 

 magnified. — After Brefeld. 



require to be treated with a dilute alkali, as a weak solution of am- 

 monia or potassic hydrate, which causes tlie hyphae to swell up to their 

 original proportions before drying ; care must be taken that the hyphae 

 and spores are not unduly swollen, or serious mistakes may be made. 



(6) In the careful study of the Moulds it is necessary to resort to arti- 

 ficial cultures of the different species, in order to be able to follow them 



