12 BURTON EDWARD LIVINGSTON 



needed in our experimentation, are already in use in many 

 manufacturing establishments. 



The initial expense connected with the sort of laboratory of 

 which I am dreaming will retard the making available of these 

 much needed facilities, but a tardy recognition of the value of 

 plant processes to mankind should eventually place at the dis- 

 posal of plant physiology at least as elaborate apparatus as is 

 now emploj^ed by moderzi astronomy. Almost as little of really 

 lasting value (in connection with higher plants, at any rate) 

 may be expected ol a physiologist in his present laboratory as 

 might be expected of an astronomer compelled to work in an 

 attic room with a dormer window! 



Internal conditions. Internal conditions, within the plant, 

 have received much attention, from the beginning of physio- 

 logical studies, and the last quarter-century has seen a rapidly 

 increasing interest in these, mainly from the physico-chemical 

 point of view. The whole science of biochemistry, and even its 

 very name, have developed practically within the period since 

 this University was founded. A general physical chemistry 

 of cells, which was new to physiology in the 90's, has broadened 

 and deepened to form a much more special chemistry and physics 

 of physiological solutions, and now the new field of colloid 

 chemistry is rapidly being opened for physiological study. Such 

 words as enzyme, semi-permeable membraiie, protoplasm, as 

 these were first used, are becoming unsatisfactory, as the things 

 that they connote are better understood. These generally 

 descriptive words will be retained, but their meanings to the 

 physiologist of today are vastly different from their meanings to 

 similar students of twenty-five years ago, and future students 

 will read into them much that we do not now suspect. 



The whole subject of cell membranes, as these influence dif- 

 fusion rates and turgor, is undergoing a thorough overhauhng. 

 I may mention, for example, that the cell wall was regarded as 

 almost always readily permeable to all plant solutes, at the end 

 of the last century; and now we may not discuss semi-permea- 

 bility of plant membranes without considering these walls. 

 Some of the recent studies upon the permeabihty of cell walls, 



