EVIDENCE PKOVING THE STATEMENT OF THE CASE 115 



most remarkable. Let us take a section of one side of 

 the brain, fig. 18, and what do we see ? 



Fig. 18. Section of one hemisphere of the brain, showing the mass of grey- 

 matter, built up of thinking cells, covering the surface of the brain and 

 the fibres converging to the spinal cord at the base of the brain, or that 

 part of the brain which is in the neck. (From Quain's Anatomical 

 Plates, " The Nerves of the Human Body " (reduced), 1839, p. 17.) 



The main facts are : within the skull is a mass of 

 cells of wonderfully complex structure. Fig. 1 9 gives a 

 poor illustration of one of these all-important objects ; 

 they are very minute indeed. They vary in form 

 enormously ; but there is always the nucleus and pro- 

 bably nucleolus, even although we may not be able to 

 see the latter. 1 They cover the whole of the surface of 



1 Very great difficulty often exists in being able to see the details 

 of these minute objects. The difficulty is frequently got over by a 

 process which is technically called "staining." The object is placed 

 in coloured or other fluids, and certain parts of the structure absorb 

 certain of the colours, or are chemically reacted on to give colour, 

 and by this simple means the cells or the various details are often 

 made visible by the microscope. But treating the cell in this way, 



i 2 



