DIATOM MOTION. I03 



Biitschli,^^' P. Hauptfleisch, t O. Miiller, i R. Lauterborn,^ 

 are the principal names. 



Hauptfleisch sought to demonstrate by staining methods 

 the existence of fine protoplasmic threads issuing through 

 pores in the valves, penetrating the coleoderm, and resembling 

 in general the threads of protoplasm already demonstrated by 

 Klebs in the jelly-sheath of certain desmids. He laid special 

 stress on the "crawling edge" of the frustule, meaning 

 apparently the angle of the valve between raphe and girdle. 

 This investigator's account is not quite convincing, and his 

 conclusions have so far failed to find general acceptance. In 

 certain important points, indeed, he is manifestlj' wrong. 

 One is bound to say, however, that a confirmation of the 

 general Hauptfleisch conception would furnish an explana- 

 tion which is still lacking for certain movements of some 

 species. It is to be remembered, also, that the argument of 

 L. Schiittll for the existence of "external plasma" is very 

 cogent, and all the stronger for being based on studies 

 directed to another end altogether. 



Prof. H. ly. Smith, making use of a device not altogether 

 new, made observations on Pinimlaria in indigo emulsion. 

 He saw in this wa}' a thick layer of coleoderm upon the 



*:Mittheilnngen iiber die Bewegung der Diatonieen. Verhandl. des 

 Naturliist.-nied. Vereins zu Heidelberg. 1891. 



t Die Ortsbewegung der Bacillariaceen. Mittheil. naturwiss. Vereins 

 fiir Neu-Verpominern und Riigen. 1895. 



% Various papers in Deutschen Bot. Gesellschaft. 1889-1897. O. 

 Miiller has been a tireless student of the diatoms, not confining himself 

 to the "Bewegung." In the polemics of the subject he is picturesque 

 and formidable. 



<! Berichte der Deutsch. Bot. Gesellschaft, 1894. Also more elabo- 

 rately in the magnificent work : Untersuchungen iiber Ban, Kerntheil- 

 nng und Bewegung der Diatomeen. Leipsig. 1896. 



II Centrifugal und simultane Membranverdickungen. Jahrbiichern 

 fiir Wissenschaftliche Botanik. 1900. 



