176 THE BEGINNINGS OF LIFE. 



can be easily discriminated. With regard to the 

 first appearance of these Dr. Hassall says: C I have 

 observed many times the emission of the spore in a 

 coloured infusion, and then noticed that the agitation 

 of the granules l by the motion of the cilia is not felt 

 until about a fourth part of the spore has been released.' 

 Prof. Unger saw these spores moving about for more 

 than two hours, but when they were covered by a thin 

 slip of glass, as during the observations of Dr. Hassall, 

 they never continued to move for more than nineteen 

 minutes. Dr. Hassall says : c The vibration of the 

 cilia continues sometimes after the spore is arrested, 

 only it is not sufficiently strong to displace the cor- 

 puscle. When at last they cease to move, the contour 

 of the spore undergoes during some instants a sensible 

 alteration, which announces, perhaps, the decomposi- 

 tion or the absorption of the vibratile organs 2 . The 

 motionless spore delays not to modify itself once again : 

 it becomes spherical ; the green matter distributes itself 

 equally, and the episporic membrane, in part reabsorbed, 

 at last escapes the sight; very soon germination com- 

 mences . . . The elongation of the filaments 

 progresses, one might say by eye-sight ; for I have 

 measured more than once an increase of three-twentieths 

 of a millimetre in an hour.' The formation of the 

 spores always takes place during the first hours of the 



1 Of carmine or indigo. 



2 The rapid formation and disappearance of the cilia surrounding 

 these spores are features of extreme interest. 



