4 go THE BEGINNINGS OF LIFE. 



Hydatina ^ eggs' had been kept for a time within a 

 developmental chamber (in which they had been ex- 

 posed to unnatural conditions), their substance under- 

 went segmentation into a multitude of Monads. 

 Dr. Gros ^ has, moreover, observed that Rotifers and 

 Rotifer-germs occasionally become putrid and resolve 

 themselves into a dense swarm composed of thousands 

 of Bacteria. 



The facts just mentioned are thoroughly in accord- 

 ance with previous observations, from which we have 

 learned that an organic matrix capable of giving birth 

 to a higher form may, when subjected to the influence 

 of more and more unfavourable circumstances, give 

 birth to lower and lower forms 2. But although ana- 

 logous phenomena have been already recorded, there is 

 room for surprise when we find that the egg of one of 

 the largest and most complex of the Rotifers, instead 

 of undergoing its own proper phases of development, 

 may, under one set of comparatively unfavourable 

 conditions, yield a dozen or more Ciliated Infusoria, 

 whilst under still less propitious influences it may pro- 

 duce hundreds of active Monads^ or even resolve itself 

 into a swarming brood composed of thousands of the 

 simplest living units. 



^ Loc. cit., pp. 440, 472. 



2 An 'embryonal sphere' derived from Nitella may for instance be 

 transformed into a Ciliated Infusorium, though under less favourable 

 conditions it either segments into Monads or becomes resolved into 

 a swarm of Bacteria— to say nothing of other possible modes of trans- 

 formation. (See pp. 401-406.) 



