1 86 PROTOPLASM 



figures, does not really correspond to its natural appearance. 

 In liis figures he depicts it, as a rule, just as has been done 

 by me as well as by the many observers of the reticular 

 structure of protoplasm, but he declares that in reality 

 the contents of the alveoli appear dark and their walls light. 

 Thus on p. 454 (1889) he says the honeycomb struc- 

 ture consists " of vacuoles which are enclosed on all sides by 

 a thick white (' plus blanche ') substance, which in pre- 

 parations stains less, and contains a more strongly staining, 

 darker, and probably fluid substance " (contents of the 

 alveoli or enchylema). I must confess that to me these 

 statements, which directly contradict both my experiences 

 and those of all former observers, seem scarcely explicable. 

 With too high a focus the contents of each alveolus give 

 the*appearance of a dark point, as has been described already 

 in the case of the oil-foams (see above, p. 25), yet it seems 

 to me hardly possible that this circumstance should have 

 led Kiinstler to his view. The statement with regard to the 

 greater staining power of the contents of the alveoli is also 

 inexplicable to me. Since, however, I am in complete 

 agreement upon this point with all other observers of the 

 so-called reticular structure, I think I may leave alone 

 these contradictory statements of Kiinstler. 



Kiinstler takes this opportunity to admit (p. 454) that 

 my comparison of the structure of protoplasm with the struc- 

 tural relations of a foam gives " une idee assez exacte de ce 

 que 1'observation microscopique directe revele." Although, 

 as has been said, he gladly accepts this comparison, yet in 

 a footnote he combats very energetically my attempts to 

 explain or illustrate protoplasmic structures with the help 

 of artificially produced foams. Since his remarks on this 

 question may serve as a prototype for similar objections, 

 which in the course of time will certainly be put forward 

 in opposition to my efforts, I take the liberty of quoting 

 them here in full. " Si, pour la simplicite avec laquelle elle 

 fait saisir cette structure, j'accepte volontiers la comparaison 

 faite par Biitschli entre la constitution de la mousse de savon 

 et celle du protoplasma, il n'en saurait etre de meme de ses 

 experiences recentes sur les emulsions, d'apres lesquelles il 



