THE STRUCTURE OF CELLS 



by Hooke became translated into a form comparable to that in 

 which the phrase is now understood. 



Nevertheless to Hooke belongs the credit of having not only 

 depicted the vesicular nature of cork and other plant-structures, but 

 also of having designated the cavities by the name of cells. 



Malpighi and Grew in the succeeding century had fully recog- 

 , nised the cellular character of plants, and even attempted a crude 

 explanation of the origin of the cells themselves, likening them to 

 the vesicular foam of beer. But accurate as was their portrayal 

 of the mature structure, they nevertheless possessed no real concep- 

 tion of the true meaning of the cell as the unit of organic life. 

 The cells were regarded as the cavities in the matrix, not as the 

 units which together constitute the organism, and it was to the wall 

 that all their observations were directed. Little or no attention 

 was seriously paid to the cell-contents. Thus, although Corti in 1772 

 had noticed the rotation of the viscous matter in the cells of Chara, 

 his discovery remained without influence, and was made again, and 

 independently, by Treviranus some forty years later. Even the 

 discovery 1 of the nucleus by R Brown in 1831-33 failed at once to 

 excite the interest of the majority of his contemporaries, nor indeed 

 does it appear that Brown himself at all fully grasped the signifi- 

 cance of his discovery. Whilst in the plant-body it was the cellular 

 structure, in the sense of Hooke, Malpighi, and Grew, which most 

 forcibly appealed to the observer, the softer tissues composing an 

 animal body were not so easily referable to a similar plan, although 

 a consideration of the blood corpuscles, and of cartilage, helped to 

 pave the way for the later generalisation. But, on the other hand, 

 the animal body was more suited to turn the attention of the 

 investigator upon the living substance, and the fundamental 

 importance of the latter seems to have been first clearly appre- 

 hended by Dujardin, who (in 1835), gave the name of Sarcode to 

 the contractile, gelatinous, diaphanous mass constituting the bodies 

 of the Infusoria which he was examining. He even succeeded in 

 distinguishing some structural details, but with the lens at his 

 command it may perhaps be doubted whether this really repre- 

 sented more than the arrangement of granular and other inclusions 

 in the living substance. 



It was, however, chiefly due to the researches of Schleiden, and 

 especially of Schwann, which were published in 1837-38, that 

 general interest became steadily focussed upon the cell-contents, 

 including the nucleus which formed a cardinal point in their famous 

 cell-theory. And it is largely to the great influence exerted by 

 their work that the rapid advances witnessed during the next 

 succeeding decades are legitimately to be traced. It is, of course, 



1 Others, including Leewenhoeck, had already seen nudei in isolated cases, but 

 their observations were quite without influence on the development of thought. 



