22 ANDREWS. 



responsive by change of shape or relative position to compulsion 

 of interalveolar activities ; while the network substance, down 

 to its most minute subdivision, shows a true, characteristic 

 rhythm of shape and position.^ 



[i8] It is the mode of distribution and optical characters of 

 the continuous substance, as well as certain constant changes 

 that take place in these, which further make it certain that 

 in the structure of Biitschli, and beyond this to the limit of 

 vision, and again beyond this, it is the continuous substance 

 which manifests the characteristic activities of the substance, 

 protoplasm. 



[19] To sum up: there was found no optical evidence in any 

 material examined, to show that the part played by the discon- 

 tinuous substances is anything more than a passive chemical 

 and physical role ; while there was endless and ever unfolding 

 evidence that it is the continuous substance, at any given 

 moment, which sustains the role of the living protoplasm ; and 

 as far down in the scale as the human eye with its most power- 

 ful aids can trace it, it is this same continuous substance which 

 we must be content yet awhile to call the living, the physiologi- 

 cally active, stuff. 



CONTINUOUS, OR LIVING, ELEMENT, 



In dealing with the continuous element it becomes neces- 

 sary, in view of its compound nature, to subdivide verbally 

 what has hitherto been spoken of as Biitschli's lamellar sub- 

 stance, or Biitschli's network. It is necessary to distinguish in 

 various cases the whole continuous substance of the physicist, 

 which includes in a given structure both alveolar lamellae and 

 the interalveolar foam ; from the latter as a thing by itself. 

 This is the more forced upon us since we must now learn to 

 think of optical networks and lines as by no means identical 

 with those actual fibrils and networks whose existence is shortly 

 to receive proof. 



The word " network," as commonly used, brings with it an 

 element of confusion, in that it does not clearly distinguish 



^ See Striation and Contractility. 



