4-02 



THE POPULAR SCIENCE MONTHLY. 



pound top assumes a very regular, semicircular outline, as shown in 

 Fig. 4, a, where the filaments are represented by single lines ; the 

 whole of the branch b is a more highly-magnified view of a dark tip 

 at the end of one of the branches in ay and at c is shown, on a still 

 higher scale, one of the ultimate branches in b, with the spores ar- 

 ranged in rows of four around the enlarged end ; while d is one of 

 those tips after the spores have fallen away. 



The reader will please bear in mind that this figure, and all the 

 others, with the single exception of the first one, represent the object 

 as greatly enlarged the microscope used for most of the work mag- 

 nifying 650 diameters. An entire plant of the one in question (Pipto- 

 cephalis Fresceniana) is scarcely visible to the naked eye when pre- 

 pared on a glass slide for investigation with the microscope. 



Fig. 4. Piptocephalis Fresceniana. De Bary. 



That which makes this mould of particular interest is the fact that 

 it is a parasite, and cannot live unless it has some other mould upon 

 which to grow. This easily explains why it does not make its appear- 

 ance until the Mucor is well established. Here we have a true parasite 

 growing on a saprophyte ; or one mould which steals its substance from 

 another which derives its living from the bread. We will not stop to 

 reason upon the matter, or wonder how this strange state of things 

 came about, but will leave the fact as it exists to those who would 

 know the cause of all things both great and small. 



There were two or three other members of the Mucor genus which 

 grew on various cultures, but, as they differ only in minor points of 

 structure from the one treated, space will not permit of their being 

 further mentioned. 



The bones of a recently-killed dog proved to be very well adapted 

 for the growth of the largest-known species of mould. Those who 

 have a passion for scientific names may call it Phycomyces nitens. It 



