KUNSTLER'S CRITICISMS 187 



pretend expliquer cette structure par le m flange de deux 

 liquides. Quelques sp&ieuses que puissant paraitre ses 

 donn^es, je m'elfeve contre cette interpretation. Le proto- 

 plasma est une substance vivante, hautement structur^e, dont 

 la constitution est le resultat d'une Evolution particulifere, 

 qui ne saurait avoir rien de commun avec ces mixtures. 

 Comparer ces deux ordres de faits me paralt aussi inutile, au 

 point de vue de la comprehension r^elle de cette structure, 

 que de comparer une M^duse k une ombrelle, une Oursin a 

 une pdlote d'^pingles, ou certains Bryozoaires a de la dentelle. 

 Ce sont 1^ des jeux d'hasard, amenant des apparences plus 

 ou moins analogues sans qu'il y ait aucun autre point 

 commun." 



On the ground already mentioned, it may be worth 

 while to subject the unfavourable opinion expressed in this 

 passage with reference to my experiments to a more detailed 

 criticism. The quintessence of Kiinstler's train of reasoning 

 is, as he himself says, that protoplasm is a " living, highly 

 structured substance, the constitution of which is the result 

 of a special development." As regards, in the first place, 

 the significance of protoplasm as " living " substance, I am 

 naturally as strongly convinced of this as Ktinstler himself ; 

 on the other hand, our paths evidently diverge when it comes 

 to explaining the peculiar manifestations of activity which 

 distinguish protoplasm and make it a living, as opposed to 

 a not-living substance. Since Kiinstler begins his refutation 

 of my views by laying emphasis on the fact that protoplasm 

 is living, he evidently belongs to that not inconsiderable 

 number of biologists who eagerly carry on investigations 

 upon life and its products, and yet do not welcome a suc- 

 cessful attempt to get nearer to the actual causes of the 

 phenomena of life, i.e. an explanation of it as due to the inter- 

 action of physical and chemical forces under definite condi- 

 tions. The veil of secrecy and the mysterious obscurity, 

 which at the present time still hang over these processes, 

 are the very incentives whereby investigators of this kind, 

 whom I have met with frequently before, are drawn towards 

 the study of the phenomena of life ; in fact they not 

 infrequently spur them on to obscure the processes and 



