APPENDIX A LI 



activity in the human system. In 1831, the celebrated botanist, Eobert 

 Brown, announced for the first time, tliat an aureola or nucleus was 

 seen in many plants, and that this circular spot, was present in each 

 cell. In 1839, Theodore Schwann discovered that there was one uni- 

 versal principle of development in the elementary part of organisms, 

 consisting in the formation of cells. This great advance in biological 

 science is undoubtedly the most important feature of the past century, 

 and one which has given an impetus to physiological investigations, of 

 vast moment to the entire human race owing to the influence, thus exer- 

 cised on the progress of practical medicine. 



John Goodsir, the great anatomist of Edinburgh, announced in 

 1842, that the nucleus is the reproductive organ of the cell, and that 

 new cells are formed from it, in fact, that an organic continuity existed 

 between the mother cell and its descendants, through the nucleus. 

 A'^irchow in his Cellular Pathology, 1858, maintained that in patho- 

 logical structures, there is actually no cell development de novo: 

 Vv'here a cell is found, there must have been a cell before, in fact, 

 cell development is continuous by descent. 



In 1843 John Goodsir established the principle that cells are 

 the ultimate secreting agents. A nerve cell is not a secreting cell, 

 however, like the general glandular cells of the system. Nerve cells 

 through the remarkable changes which take place in them, generate 

 that form of energy, known to exist as a special outcome of a nervous 

 system and defined as " Nerve Energy " or " Nerve Force."^ A nerve 

 fibre is actually an essential part of the cell with which it is continuous, 

 and the cell and nerve fibre associated make up what is termed a 

 neuron, now known to play so important a role in the entire nervous 

 system. 



The brain, like other parts of the body, may be in a state of 

 activity, or of fatigue. When active, the nucleus increases in size, 

 and when fatigued, the neucleus diminishes, and finally shrivels up, 

 becoming in fact, useless, as far as functional activity is concerned. 

 It is very remarkable that nerve cells have not the power of repro- 

 ducing their kind, their especial power being closely connected with 

 the evolution ' of nerve energy. This is a point on which I desire to 

 place particular stress as once a portion of the brain, or other nerve 

 centre is destroyed, new brain material or a new nerve centre, cannot 

 be produced, to replace the injured parts, as takes place in other por- 

 tions of the human frame, where bones, tendons, and such like are 

 injured, nature comes to the relief, by new tissue in every respect 

 analogous to the part destroyed. This forms the key note to the 

 subject matter in hand, and demonstrates beyond doubt, with what 

 care and watchfulness, nerve tissue should be guarded, to retain 



