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 

 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, 

 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- 

 ties 2. 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 Zootomicie,' Tab. viii. fig. i. 

 - ' Trans, of Linn. Soc' vol. xxv. p. 116. 



