136 ALFRED T. SCHOFIELD^, ESQ.^ M.D.^ M.E.C.S,, ETC., ON 



inch ill diameter. The nerve cells seem to be the starting 

 point, and the centres of nntrition for the nerve fibres. 

 The nutrition of the attached fibres is indeed a more obvious 

 part of their work than the projection of impulses, which was 

 formerly thought to be their main function. Any fibre cut 

 off from its nutrient cell soon wastes away. In early child- 

 liood the cells are of a spherical, fusiform, or pyi-amidal form 

 with few or no interlacing nerve fibres. Nerve impulses, 

 starting in infancy and increasing in numbers and com- 

 plexity till adult life is reached, are believed to form inter- 

 communicating nerve fibres between the cells in every 

 direction, until in manhood though tliere are still left many 

 unbranched cells, the greater number have fibres given off 

 in every direction. In old age ngaiii a good many of them 

 appear to be broken ofi" and the cells blunted. 



Blood supply. — The grey matter containing cells is, to a 

 limited extent, analogous to an electric battery, of which the 

 wires are the nerve fibres. The vitality of these nerve structures 

 is maintained by a constant supply of fresh arterial blood. By 

 this means when the battery has discharged its nerve force, it 

 is speedily recharged, and as this occurs most often in the 

 grey matter, there is about five times as much blood circu- 

 lating there as in the Avhite or fibre matter. The great 

 proportion of blood used by the brain compared with the 

 rest of the body is certainly remarkable. While the brain is 

 only about -^ part the weight of the body, the supply of 

 blood is about one-eighth of the whole of that required by 

 the rest of the body. The system of circulation is arranged 

 so as to ensure the most constant and rapid change. The 

 interdependence of mind and body is nowhere more clearly 

 seen than in the question of blood supply. If it be sud- 

 denly cut off from any part, that part can no longer be used 

 voluntarily; if the blood be deficient in quantity the thoughts 

 often get confused and senseless ; if it be defective in quality 

 the very disposition seems changed, and the person gets 

 gloomy and morose ; if the temperature gets raised, delirium 

 sets in; if eff\ision takes place, and the blood presses 

 on the brain consciousness is lost altogether in an apoplectic 

 fit. 



Ordinary functions of brain. — The brain has already been 

 divided into four parts, and these correspond to its leading 

 functions. The cerebrum is thus chvided into upper, middle, 

 and lower regions ; or cortex, mid-brain, and medulla. The 

 first is the seat of intellectual life, or the sphere of the activities 



