WHAT IS A CELL? 



55 



goes conversion into the tissue. At the same time it 

 absorbs nutrient material, and thus, although a vast amount 

 of contractile tissue may have been produced, the germinal 

 matter which formed it may not have altered in bulk. 

 (PI. VII, fig. 25.) The fibres of yellow elastic tissue are 

 formed in the same manner, and each fibre is thickened by 

 the formation of new material from germinal matter, which 

 lies upon the external surface of each fibre (fig. 26.). 



The Formation of Nerve Fibres. The nerve fibre is 

 composed of formed material, which is structurally con- 

 tinuous with the formed material of the nerve cells of the 

 nerve centres. A nerve fibre at an early period of develop- 

 ment consists of a number of oval masses of germinal 

 matter linearly arranged. As development proceeds, these 

 become separated farther and farther from one another, and 

 the non-living tissue which is thus spun off as they become 

 separated, is the nerve. (PI. VII, fig. 27.) 



What is essential to the Cell? All that is essential 

 to the cell or elementary part is matter that is in the 

 living state germinal matter, and matter that has been in 

 the living state formed material. With these is usually 

 associated a certain proportion of matter about to become 

 living the pabulum or food. So that we may say that 

 in every living thing we have matter in three different 

 states matter about to become living, matter actually 

 living, and matter that has lived. The last, like the first, 

 is non-living, but unlike this it has been in the living state, 

 and has had impressed upon it certain characters which 

 it could not have acquired in any other way. By these 

 characters we know that it has lived, for we can no more 



