46 PROTESTS AND DISEASE 



with crystals of oxalate of lime. The septum at the base 

 bulges into the cavity constituting a columella. 



The zygospore requires some months to mature. It 

 germinates by sending out a single hypha called a promycelium, 

 which produces a sporange full of conidia, but when the 

 zygospore germinates in a nutrient medium it forms a 

 mycelium. 



Spores. Two classes of spores are to be distinguished 

 in fungi by their mode of germination : in one the whole of 

 the protoplasm passes into the germ-hypha and the empty 

 capsule is left to decay ; in the second group, that to which 

 Mucor belongs, the spore retains part of the protoplasm, 

 grows, and remains part of the developing plant. 



Spores of the first group will germinate in water, those of 

 the second require nutrient media. 



Four spores are shown at 8 in Fig. 9 ; the two upper 

 from a sporangium needled in a drop of water, the two lower 

 in a weak infusion of plum- jam. Only the latter are changed 

 being swollen and having a double contour and a central 

 vacuole. From one a hypha has grown, some neighbouring 

 spores had two, and others three such. Two days later a 

 hypha which had eight lateral branches was sketched. In 

 its central part granules were seen to flow a considerable 

 distance towards the growing point, and at the same time 

 other granules were flowing in the opposite direction. Not 

 more than one per cent, of the spores in this culture germi- 

 nated. 



