PROGRESS IN ANATOMY AND PHYSIOLOGY 



a name. That this newly recognized structure must be 

 important in the economy of the cell was recognized by 

 Brown himself, and by the celebrated German Meyen, 

 who dealt with it in his work on vegetable physiology, 

 published not long afterwards ; but it remained for an- 

 other German, the professor of botany in the university 

 of Jena, Dr. M. J. Schleiden, to bring the nucleus to 

 popular attention, and to assert its all-importance in the 

 economy of the cell. 



Schleiden freely acknowledged his indebtedness to 

 Brown for first knowledge of the nucleus, but he soon 

 carried his studies of that structure far beyond those of 

 its discoverer. He came to believe that the nucleus is 

 really the most important portion of the cell, in that it 

 is the original structure from which the remainder of 

 the cell is developed. Hence he named it the cytoblast. 

 He outlined his views in an epochal paper published in 

 Miiller's Archives in 1838, under title of " Beitrage zur 

 Pbytogenesis." This paper is in itself of value, yet the 

 most important outgrowth of Schleiden's observations of 

 the nucleus did not spring from his own labors, bat from 

 those of a friend to whom he mentioned his discoveries 

 the year previous to their publication. This friend was 

 Dr. Theoclor Schwann, professor of physiology in the 

 university of Louvain. 



At the moment when these observations were com- 

 municated to him Schwann was puzzling over certain 

 details of animal histology which he could not clearly 

 explain. His great teacher, Johannes Miiller, had called 

 attention to the strange resemblance to vegetable cells 

 shown by certain cells of the chorda dorsalis (the em- 

 bryonic cord from which the spinal column is devel- 

 oped), and Schwann himself had discovered a corre- 



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