8 THE CELL 



protoplasm and naked sarcode. It is true that lie retains the 

 term " cell," which was introduced into anatomical language by 

 Schleiden and Schwann ; but he defines it (I. 30) as : a small mass 

 of protoplasm endowed with the attributes of life. 



Historical accuracy requires that it should be mentioned that 

 in this definition Max Schultze reverted to the older opinions held 

 by Purkinje (I. 22-24) and Arnold (I. 1), who endeavoured to 

 build up a theory of granules and masses of protoplasm, but with- 

 out much result, for the cell theory of Schwann was both more 

 carefully worked out, and more adapted to the state of knowledge 

 of the time. 



The term, a small mass of protoplasm, was not intended by 

 Max Schultze and other investigators even then to mean so simple 

 a matter as appears at first. The physiologist, Briicke (I. 6), 

 especially came to the correct conclusion, gathered with justice 

 from the complexity of the functions of life, which are inherent in 

 protoplasm, that the protoplasm itself must be of a complex con- 

 struction, that is must possess "an extremely intricate structure," 

 into which, as yet, no satisfactory insight has been gained owing 

 to the imperfections of our means of observation. Hence Briicke 

 very pertinently designated the "ultimate particle" of animals and 

 plants, that is the mass of protoplasm, an elementary organism. 



Hence it is evident that the term " cell " is incorrect. That it< 

 nevertheless, has been retained, may be partly ascribed to a kind of 

 loyalty to the vigorous combatants, who, as Briicke expresses it, 

 conquered the whole field of histology under the banner of the 

 cell-theory, and partly to the circumstance, that the discoveries 

 which brought about the new reform were only made by degrees, 

 and were only generally accepted at a time when, in consequence 

 of its having been used for several decades of years, the word cell 

 had taken firm root in the literature of the subject. 



Since the time of Briicke and Max Schultze, our knowledge of 

 the true nature of the cell has increased considerably. Great 

 insight has been gained into the structure and the vital properties 

 of the protoplasm, and in especial, our knowledge of the nucleus, 

 and of the part it plays in cell-multiplication, and in sexual repro- 

 duction, has recently made great advances. The earlier definition, 

 " the cell is a little mass of protoplasm," must now be replaced by 

 the following : " the cell is a little mass of 'protoplasm, which contains 

 in its interior a specially formed portion, the nucleus." 



The history of these more recent discoveries will be entered 



