5 6 PROTOPLASM. 



cause matter artificially to exhibit the characters of the dried 

 leaf, the lifeless wood, shell, bone, hair, or other tissue, than 

 we can make living matter itself in our laboratories. 



Cells are not like B 'ricks in a Wall. Cells forming a 

 tissue have been compared with bricks in a wall, but the 

 cells are not like bricks, they have not the same con- 

 stitution in every part, nor are they made first and then 

 embedded in the mortar. Each brick of the natural 

 wall grows of itself, places itself in position, forms and 

 embeds itself in the mortar of its own making. The whole 

 wall grows in every part, and while growing may throw 

 out bastions which grow and adapt themselves perfectly to 

 the altering structure. Even now it is argued by some 

 that because things, like fully formed cells, may be made 

 artificially, the actual cells are formed in the same sort 

 of way an argument as forcible as would be that of a 

 person, who after a visit to Madame Tussaud's Exhibition, 

 seriously maintained that our textures were constructed 

 upon the same plan as the " life-like " wax figures he had 

 seen there. 



Every one who really studies the elementary parts of 

 tissues and investigates the changes which occur as the 

 germinal matter passes through various stages of change 

 until the fully developed structure results, will be careful 

 not to accept without due consideration the vague generali- 

 sations of those who persist in authoritatively declaring that 

 the changes occurring in cell growth are merely mechanical 

 and chemical, although they are unable to produce by any 

 means at their disposal a particle of fibrine, a piece of carti- 

 lage, or even a fragment of coral. They avoid the difficulty 



