70 THE CELL DOCTRINE. 



his application by actual demonstration of the first 

 of these points to so large a variety of physiological 

 and pathological processes, to which is added original 

 conception in the prominence given to the connec- 

 tive tissue corpuscle and the canalicular system, 

 whatever may be the truth with regard to either. 



SARCODE OF DUJARDIN. PROTOPLASM OF MAX SCHULTZE. 



1835-61. 



Dujardin* had, in 1835, discovered in the lower ani- 

 mals a living, moving, contractile substance, which 

 he called sarcode. The peculiar appearances of this 

 substance attracted the attention of many observers, 

 among whom were Meyen,f Huxley, Max Schultze, 

 John Muller, and others, who thought it peculiar to 

 the lower animals, and there was assigned to it a 

 property of " irritability without nerves."! 



The observation of Siebold, that the yolk glob- 

 ules of Planaria exhibit contractions and expansions, 

 which with suitable care continue for hours, and the 

 discoveries which followed of similar movements 

 and changes in form, led Kolliker|| to express the 

 conjecture that the contents of all cells are contractile. 

 Virchowl attributed the movements to a contractile 



* Dujardin, Ann. d. Sciences Nat., torn, iii et v. 

 f Meyen, Einschlagige Liter, in E. Ilaeckel's Die Radiolaren. 

 1862. 



J Schultze, Max, Organis. d. Polythalamien. 1854. 

 g Siebold, Froriep's Notizen, Nr. 380, p. 85. 

 || Kolliker, Wurzb. Verb., Bd. viii. 

 fl Virchow, Archiv, Band v. 



