WITH THE MICROSCOPE. 315 



which is a layer of formed material or lifeless matter varying in thick- 

 ness in different cases, bdt which has in all resulted from the death oj 

 Particle after particle of the first. 



That the formed material is deposited as I have described is 

 proved by watching the changes which occur in such a structure as 

 ordinary mildew, represented in pi. XLI, fig. 259. The various 

 drawings of mildew, in different stages of growth, are careful copies 

 from nature, and should be attentively studied with the aid of the 

 explanations. 



The germinal matter which in some of the plates is known by its 

 granular appearance, and in others by its being coloured red, is in fact 

 the only active part of the cell. Nothing can be said to live which does 

 not consist of germinal matter. In pi. LXIII, fig. 393, and in pi. XLI, 

 % 2 57> are represented some growing muscular fibres. The masses of 

 germinal matter are large and well-formed. The so-called nuclei of the 

 nerve fibres ramifying among them also consist of living or germinal 

 matter. In tendon, and various forms of fibrous tissue, the so-called 

 'nucleus' is the germinal matter, and the fibrous matter is the formed 

 material (s<?<?pl. LVIIJ.fig. 369). So also in cartilage the same simple 

 distinction can be made. The so-called ' intercellular substance ' or 

 'matrix,' figs. 367, 368, is no more intercellular than the so-called 

 ' wall ' of an epithelial cell is intercellular* 



In young tissues the proportion of germinal matter to the 

 formed material is invariably very great compare the young nerve 

 cells, represented in pi. LXVIII, figs. 410, 411, with the fully-formed 

 nerve cells in pi. LXVII. Also observe the relative quantities of 

 germinal matter and formed material in the young, and advanced 

 cells, represented in pi. LVII, figs. 358, 359, and 360. 



382. Of the Nature of " Irritation " and " Inflammation." 

 Let us now consider the wonderful effects which ensue from 

 a change of the circumstances under which the " cell " is placed. 

 Suppose the hard formed material which interferes with the access 

 of pabulum to the germinal matter to be ruptured, or softened 

 by the action of fluids, so that pabulum may more readily 

 come into contact with the germinal matter what happens ? 

 The latter increases. It absorbs the nutrient matter, and may 

 even take up the softened and altered formed matter, which was 

 itself produced from germinal matter at an earlier period. These 

 stages are seen in figs. 361, 362. In fig. 363, the original 



* " Of the formation of the so-called intercellular substance of cartilage and 

 of its relation to the so-called cells." Transactions of the Microscopical Society, 

 March, 1863. 



