KUNSTLER'S CRITICISMS 187 



pretend expliquer cette structure par le melange do deux 

 liquides. Quelques spe*cieuses que puissent paraitre ses 

 donnees, je m'eleve centre cette interpretation. Le proto- 

 plasma est uue substance vivante, liautement structuree, dont 

 la constitution est le resultat d'une evolution particuliere, 

 qui ne saurait avoir rien de commun avec ces mixtures. 

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

 point de vue de la comprehension reelle de cette structure, 

 que de comparer line Meduse ti une ombrelle, une Oursin a 

 une pelote d'epingles, ou certains Bryozoaires a de la dentelle. 

 Ce sont la des jeux d'hasard, amenant des apparences plus 

 on 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 Klinstler'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 Kiinstler 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 



