70 



MORPHOLOGY OF THE MUCORS. 



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The genus Phycomyces is characterised by the possession of 

 spinous prolongations on the suspensores and sporangiophores, 

 which latter are unbranched, olive-green in colour, and possess 

 metallic lustre. 



One species of this genus, PJiycomyces nifens, is plentifully 

 met with in empty oil-casks, on oil-cakes, in concentrated fodder 

 works, and similar places, and puts forth stiff, upright spor- 

 angiophores 7 to 30 cm. long and 50 to 150 ju. in diameter. 

 These become crowned with an initially orange, but finally 

 black, globular sporangium, 0.25 to i.o m.m. across, exhibiting 

 a cylindrical columella and filled with ellipsoidal, yellow-brown, 



thick- walled endospores, ib to 30 

 /x long and 8 to 15 /x broad. It 

 has not yet been ascertained 

 whether this species feeds on the 

 fats present in the aforesaid 

 medium ; in fact, the whole ques- 

 tion of the decomposition of fats 

 by moidd fungi (i:^ 233), on which 

 sundry observations have been 

 communicated by R. H. Schmidt 

 I.) and by Ritthausen and Bau- 

 MANN (II), is a matter still 

 requiring closer attention. 



The genus Mucor is distin- 

 guished by the absence of spiny 

 branches on the suspensores, by 

 the silky gloss of the sporangio- 

 phores, and by the liquefaction 

 of the ripe sporangium membrane. The contents of the ripe 

 sporangium are only partly consumed in building up the spores, 

 the remainder serving as a matrix wherein the individual ripe 

 spores are embedded and separated from each other. Now this 

 matrix is capable of distension, and holds the crowd of spores 

 together, even in microscopical preparations ; whereas on the 

 other hand the sporangial membrane, being liquefiable, is either 

 quite invisible in such (aqueous) preparations, or at most is only 

 seen as a residual trace at the point of attachment to the sporan- 

 giophore. An attempt is made to portray this in Fig. 112. The 

 outside of the sporangial membrane is found to be more or less 

 closely set with crystals of calcium oxalate. A few of the species 

 composing this genus are pathogenic, and therefore interesting to 

 the pathologist, since they are able to set up mycosis (in this case 

 Mucor-mycosis) or fungification of the body they have infested, 

 or into which they have been artificially inoculated. Of these 

 pathogenic species of Mucor— some of which have not yet been 

 properly examined and classified in a botanical sense — mention 

 may be made of the following : Mucor pusilhis, discovered by 



Fig. 



-Mucor mucilagineus 

 Brefeld. 



Newly burst sporangium, m is the 

 membrane, z the matrix, sp the spores. 

 Several of the latter have been 

 squeezed out of the sporangium. 

 Magn. 300. (After Brefeld.) 



