490 PRACTICAL BOTANY 



the white of egg : coagulate it, and harden in alcohol. Sections 

 are then to be cut of the whole mass, together with the bodies 

 embedded, and they are to be mounted and examined in the 

 usual way. 



Attempts should also be made to cultivate the mature spores in a 

 very weak decoction of French plums as above directed for the 

 conidia. 



Among the Moulds which appear with constancy on bread 

 kept under a bell-glass, as also on other organic bodies, is 

 Penicillium : it may be readily distinguished from Aspergillus 

 by its lower growth, more velvet-like appearance, and blue-green 

 colour, while the latter shows a higher growth, so that the 

 individual conidiophores may be seen with the naked eye : its 

 colour is an olive-green. 



Remove a small piece from a pure patch of Penicillium which has 

 been recognized by the above characters : tease it out with needles, 

 then moisten it with alcohol, and mount in water. Examine it 

 under a high power, and observe the branched, septate mycelium, 

 which frequently forms a very dense mat : this is especially the 

 case if it be grown on Pasteur's solution with sugar. Note that 

 certain branches, which grew up from the substratum, end in a 

 brush of closely arranged parallel branches, and that each branch 

 is terminated by a string of conidia : these are formed by 

 basipetal abstriction, in the same way as in Aspergillus. 



The conidia may be germinated in the same way as those of 

 Aspergillus, and with suitable precautions pure cultures may be 

 grown on various nutritive substrata. 



