54 THE PHASES OF 



seemed to consider it a necessity to include all possible form- 

 elements within this improved scheme of a cell. 



S. Strieker,* in 1868, for instance, discusses the question 

 how large a lump of protoplasm ought to be to entitle it to the 

 name of a cell, and comes to the conclusion that we should 

 speak of a cell only if the lump exhibits growth and repro- 

 duction. At that time it was already known that, with the 

 highest powers of the microscope, very minute, just perceptible, 

 granules grow under our very eyes. The doctrine of the 

 so-called zymotic diseases almost necessitates the assumption 

 that the carriers of the contagion are organisms, not subject 

 to our observation even with the best lenses. Are not the 

 innumerable corpuscles in decomposing liquids individual organ- 

 isms in spite of their minute size, which renders them hardly 

 perceptible even with our best optical apparatus? And all 

 these minute organisms should be called cells. Very probably, 

 a granule of living matter may be altogether too small to be 

 perceived, and such a granule will agree as little with the idea 

 of a cell as it will with the idea of an elementary organism. 



What at that time was called a structureless, elementary 

 organism, a " cell/ 7 I have demonstrated to consist only in part 

 of living matter, while even the minutest granules of this matter 

 are endowed with manifestations of life. The cell of the 

 authors, therefore, is not an elementary, but a rather compli- 

 cated organism, of which small detached portions will exhibit 

 amoeboid motions. 



The nucleus cannot be considered an essential part of the 

 cell, for all good observers know that there are cells destitute of 

 nuclei, and some authors have distinguished nucleated cells from 

 " cytodes" cell-like bodies devoid of nuclei. (See page 2.) 



We can escape from the difficulties of a definition only by 

 abandoning the designation " cell/ 7 in the sense of the zoologists. 

 By this, our usual terminology will remain unaltered. The 

 amoeba, f. i., or the colorless blood-corpuscle, the protoplasmic 

 lump in the colostrum, the pus-corpuscle, are formations to 

 which the term " cell " is not usually applied. We need no such 

 word for properly designating what we mean by saying the 

 amoeba, the colorless blood-corpuscle, etc., are alive ; or the 

 amoeba, the colorless blood-corpuscle, are organisms. 



Such were my conclusions in 1873 (I. c.J, and here I wish to 

 add a few remarks more as to the propriety of the term " cell." 



*Handbuch der Lehre von den Geweben. Art. " Allgemeines iiber die 

 Zelle." 1868. 



