The Microscope. . 201 



speaking, not in harmony with the present state of knowledge ; 

 nevertheless it is retained in science, and in fact it would be dif- 

 ficult to replace it owing to its universal use. Professor Sachs 

 in his " Physiology of Plants," Lecture VI., declares that " the 

 true meaning of the word cell may be quite clear to but few, the 

 less so since biologists themselves even now hold and discuss the 

 most different opinions upon it." 



According to Canon Carnoy, " Cells are elementary organisms 

 or individualities of organized beings." This view is now very 

 commonly accepted, and indeed cells are now commonly re- 

 garded as independent living beings, which sometimes exist by 

 themselves alone, and sometimes are joined with others, millions 

 of them, to constitute a cell-colony or, as Hajckel calls it for 

 plants, " a cell republic." In fact, according to this view the 

 cells constitute the individual somewhat as the zooids constitute 

 the individual Hydrozoan or the polypi constitute that of the 

 Actinozoan. 



Many however, with Sachs, consider cells as only one of the 

 products of the formative forces so universally found in matter, 

 and particularly so in organic substance. In the inorganic sub- 

 stance the highest expression of formative force is the crystal, 

 but not all matter attains to that state although all inorganic 

 matter tends to it, and certainly would reach it if the proper 

 conditions were always and everywhere realized. In the organic 

 world we find the cell as the highest realization of formative 

 force ; whether this form is always realized is another question, 

 but it remains nevertheless true that the cell is the organic unit, 

 just as the molecular crystal is the unit of composition in/ the 

 inorganic world. We are therefore justified in a certain measure 

 in considering cells as elementary organisms or individualities 

 of organized beings. S. Howard Vines expresses this view in 

 the following words. " The body of a plant, like that of an ani- 

 mal, consists of one or more structural units, which are termed 

 'cells,' and in plants, as in animals, the cell consists essentially 

 of an individualized mass of protoplasm." M. Foster considers 

 cells as only anatomical units, but rejects them as physiological 

 units. Schwann and Schleiden, he says, " considered the proper- 

 ties of the cell, as they described it, as the mechanical outcome 

 of its build," and further on he says, " With this anatomical 

 change of front the physiological cell-theory was utterly de- 



