CHAPTER I. PROTOZOA (continued) 



SECTION H. THE STRUCTURE OF ANIMAL AND VEGETABLE 

 CELLS l 



IN reviewing the course of development of our knowledge of 

 organic nature, there stands out one epoch-making discovery, that 

 of the chambered structure of plants, made by Hooke in 1665, 

 which was destined not only to profoundly modify the older con- 

 ceptions as to the intimate organisation of animals and plants, but 

 also to place in clear relief the fundamental unity which underlies 



FIG. 1. 

 Facsimile of part of a figure by Hooke representing cells of vegetable tissues (cork). 



the apparently endless variety of external form. But, as in the case 

 of most discoveries of wide-reaching import, the general recognition 

 of the true nature of the cell did not emerge at once in its modern 

 form, nor was it in reality the outcome of the work of any single 

 investigator. Indeed, nearly two hundred years elapsed before the 

 first enunciation of the doctrine of a cellular structure of plants 



1 By J. B. Farmer, D.Sc., M.A., F.R.S. (1902). 



I 



