378 THE BEGINNINGS OF LIFE. 



to observe what became of these bodies, I carefully 

 watched one for some hours, and observed the follow- 

 ing:— First, the movement by protrusion became gradu- 

 ally restricted till it was extinguished, the mass returning 

 to the ovoid form it possessed originally. The exterior 

 also seemed to become more rigid, although I do not 

 think there was any distinct cell-wall. Secondly, the 

 whole exterior became covered with very minute cilia in 

 constant vibration, by which the mass was kept in a 

 state of agitation within the containing cell. The total 

 motion was curtailed, of course ; but in bodies which I 

 noticed moving in the water undistinguishable from 

 them, the motion was rapid and rolling. Beyond this 

 point I was unable to extend my observations on their 

 life-history.^ This change from the amcsboid to the 

 ciliated state was rapidly effected, since Dr. Hicks had 

 seen it brought about in the course of two hours ^ . 



We will now refer to some observations, previously 

 alluded, to and made by Mr. H. J. Carter, which also 

 furnish us with particulars of the greatest interest. 



At pp. 187-190 of vol. i. we described the early changes 

 taking place within an internode of a Nitella which is 

 about to die. We then quoted Mr. Carter's description 

 of the mode of formation of the ^gonidial' cell, as 

 he at that time called it, and have now to follow his 



^ Dr. Gros had, however, long before — and even anterior to the date of 

 Pringsheim's observations — declared that the nuclei of the spiral bands 

 of Spirogyra might individualize themselves and become converted into 

 Monads which subsequently developed into different forms of Ciliated 

 Infusoria. (See ' Bullet, de la Soc. de Nat. de Moscou/ 1 851, p. 477.) 



