REMAK, ON THE BASIS OF THE CELL-THEORY. 277 



organs are generally known, is a highly improbable one. 

 In fact, although cnida exist in certain medusse and in the 

 actiniae, animals undoubtedly endowed with a stinging power, 

 as well as in the Zoantharia, to Avhich a similar power is 

 generally attributed, though erroneously according to Mr. 

 Lewes, they are found on the other hand in the Turbellarise 

 and in the Eolidce, among Avhich no species is knoAvn to 

 possess any urticating property. Mr. Lewes, by conclusive 

 observations, has further shown that the cnida do not para- 

 lyse the motions of minute animals (crustacea) which have 

 been seized by an Actinia. (It is true observations to the 

 contrary might be cited, with respect to the cnida of the 

 Iwdra and the trichocysts of certain Infusoria.) Lastly, the 

 great extent to which the cnida are developed in the internal 

 organs, denominated " mesenteric filaments " in the Actiniae, 

 renders, as Mr. Lewes rightly remarks, the urticating 

 function of these organs extremely doubtful. 



On the Embryological Basis of the Cell-theory. By 

 Professor Bob. Remak. 



(Eeichert aud Du Bois. Reymond. 'Archiv,' 1862, No. ii, p. 230.) 



Since the conclusion of my " Besearches on the Develop- 

 ment of the Vertebrata " (1851-55), and the devotion of my 

 attention to other subjects, I have not ceased to take interest 

 in the progress of histological literature ; and although I 

 have frequently remarked that my labours on that subject 

 have been either entirely overlooked or insufficiently acknow- 

 ledged, 1 have not on every occasion thought it requisite to 

 enter into a polemical discussion. I am compelled, howev.er, 

 to make an exception to this course, in the case of an Essay 

 by Professor Max Schultze, of Bonn, which appeared in this 

 ' Journal ' in the beginning of last year, entitled " On Muscle- 

 Corpuscles, and what should be termed a ' cell,^ " because the 

 paper in question sets out openly with the claim to upset all 

 the foundations of the prevailing cell-theory, part of which 

 had been laid l)y my labours ; and also because I think that, 

 offering these anti-critical remarks, I may be able to protect 

 the science to which I have formerly devoted so much time 

 against some misunderstanding and error. 



Schultze proposes himself to put an end to the contention 

 respecting the so-termed ^^muscle-corpuscles,'^ their existence. 



