THE LIVING SUBSTANCE. 



99 



sea-urchin and rotifer eggs before the protoplasm reaches a 

 more uniform arrangement preceding first cleavage. In some 

 living epidermal cells of a small marine fish, I have found a 

 curious whorled effect produced by the interalveolar substance 

 lying in somewhat concentric but branched lines, these con- 

 trolling the form of the network to such an extent that the 

 optical reticulum was in places triangular; yet closer observa- 

 tion showed that the vesicles themselves had true fluid contours 

 notwithstanding. As pathological states set in, preceding death 

 of the cells, the concentric, or whorled, arrangement gave place 

 to a more and more regular and even structure of Biitschli, 

 the relaxed continuous substance becoming less obvious, the 

 vesicles swelling very perceptibly and their hue changing also 

 to a darker and bluer tone. This by lamplight. 



In transversely striated muscle bands in a rotifer, I have 

 seen coarse striae which were visible in states of medium 

 extension, separate during greater extension so as to become 

 resolved into double striae. Between these, vertical alveolar 

 walls could be seen at happy moments of optical conditions. 

 At first only each alternate stria would so separate, but in 

 rare and extraordinary extension of the muscle band the other 

 alternating striae would half reluctantly separate also, and show 

 their structure to be the same. Here were evidently reserve 

 powers of extension and of elasticity. 



The rapidity with which the elements of a given vesicular 

 structure can be re-organized for contractile activities, is a 

 very important point which must not be passed over. If I 

 say that such can take place "in the twinkling of an eye " it 

 may sound like exaggeration, yet such is indeed often the fact. 

 Of course where an existing structure of Biitschli remains 

 unaltered, the contraction is referable to the ever present 

 ectosarcal nature of the continuous substance, having ready 

 prepared just the structure for organized action of the sub- 

 stance to take place in.^ 



[97] Cilia are truly but external striae, both as regards their 

 origin and mode of formation. 



Most remarkable are the phenomena of the aster rays in 



^ See Substance as Such. 



