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THE BEGINNINGS OF LIFE. 



391 



refractive granules frequently make their appearance 

 within the mucus-layer of the cell ; and when the former 

 shrinks from the latter, these spherical cells become 

 wrapped up in it.' Each of the spherical cells usually 

 develops a blind tube, which sometimes penetrates the 

 cell wall of the Spirogyra for the exterior liberation of 

 its contained germs, though others of them may commu- 

 nicate with adjacent cells. And occasionally one of these 

 inosculating spherical cells may send its tube « through 

 the septum of the cell into the resting-spore of the 

 next cell, which, being full of nutritious matter, im- 

 mediately furnishes food for the whole brood.' Mr. 

 Carter says that the granules of the tubulating cells 

 are of different sizes, and motionless at first ; though 

 they subsequently 'become locomotive, swarm about 

 the cell, and then pass out of the tubular prolonga- 

 tions.' Cells of an altogether similar character were 

 also seen to develop within the dead bodies of certain 

 Rotifers \ 



^ Concerning the actual origin of these products Mr. Carter has exhi- 

 bited much vacillation of opinion. Thus, although at one time he 

 believed they were formed from a modification of the substance of the 

 organism in which they appeared, he afterwards renounced this view and 

 adopted his first notion that they were parasites whose germs had been 



,p^J Orpr^"; introduced ('Ann. of Nat. Hist/ i86r, pp. 285-288). But tubulating 



Ir. ^n^'*' germ cysts of a somewhat similar nature have been seen by Stein within 



germ cysts of a somewhat similar nature have been seen by Stein within 

 Vorticella microstoma and Vorticella nebulifera (see Pritchard's ' Infusoria,* 

 P' 357); ^nd they were thought by Stein to represent one of the modes 

 of reproduction of these Infusoria — which seems to show that they 

 appeared to him. to be formed froni the very substance of the organism 

 in which they were found. Cienkowski has also observed a similar 

 development of brood cells within encysted specimens of Na$sula viridis 



