r 



Erste Sektion: 



Cytologie und Protozoenkunde, 



Einführender Vorsitzender: Herr Prof. Dr. R. Kiemen- 

 siewicz (Graz). 



Schriftführer: Herr Dr. L. Löhner (Graz). 



Erste Sitzung. 



Dienstag, den 16. August, Nachmittags 1 / 2 3 Uhr, im Hörsaale des 

 Instituts für allgemeine und experimentelle Pathologie. 



Den Vorsitz führt Herr Prof. Dr. A. Borgert (Bonn). 



Herr Prof. Dr. J. P. Munson (Ellensburg, Wash.) hält 

 seinen angezeigten Vortrag: 



Organization and Polarity of Protoplasm. 



By J. P. Munson, Contents Ph. D., (Ellensburg, Wash.). 



Mit Tafel Ia, Ib und Ic. 



Introduction — External Evidences of Polarity — fore 

 and aft polarity in Amoeba — a Walking cell — Internal Evidences of 

 Polarity — caryolymph and metaplasm — centrosome and aster — eviden- 

 ces of persistence of centrosome and aster — nature of astral rays — nature 

 of centrosome — the aster and cy toplasm — Polarity of the Egg — 

 direction of egg-axis — general impression of specific characters — Theo- 

 retical Suggestions — development of structure and polarity. 



Introduction. 



Studies in embryology , cellineage , and cleavage of ten 

 necessitate the assumption of a polarity of the fertilized egg, 

 even where no positive evidence of such polarity has been 

 demonstrated. But the existence of such polarity is often denied 

 on the assumption that the egg, and protoplasm in general, is 

 isotropic. 



VIII. Internationaler Zoologen- Kongreß. 24 



