528 



THE BEGINNINGS OF LIFE 



^ 



witness a direct origin of Nematoids from some of the 

 thick-walled resting-spores of Vaucheria. A specimen 

 of this plant had been growing beneath a bell-glass 

 outside my window for more than a month, and por- 

 tions of it had been repeatedly examined, though on 

 none of these occasions had a single Nematoid been 



r 



seen. But^ wishing to observe the effects of a sudden 

 alteration of conditions upon some of the organisms 

 contained in the saucer, I took it into my study, and 

 kept it (still beneath a bell-jar) in a part of the room 

 away from the window — so that it was simultaneously 

 exposed to a higher temperature and to a diminution of 

 light. Four days afterwards the weed in many parts 

 was found to be shrivelled and undergoing decolouriza- 



tion. It was evidently dying. On taking up a minute 

 portion of the Vaucheria thus affected, I was much 

 surprised to see three or four active Nematoids. And 

 each minute portion subsequently examined was always 

 found to yield from three to eight of these animals, 



T 



which, on examination with higher powers, I at once 

 recognized as forms similar to those to which Max 

 Schultze had previously given the name Diplogaster\ 

 and of which I had described two or three new varie- 



J ■ 



ties^. These particular Nematoids now existed by 

 thousands in the small saucer containing Vaucheria, 

 in which not a single specimen had been seen four 

 days before, or for a month previously. They were, 



^ A form which is figured in Carus's ' Icones Zootomicse/ Tab. viii. fig- ^• 



2 t 



Trans, of Linn, Soc' vol. xxv. p. it 6. 



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