304 



ELEMENTS OF PHYSIOLOGY 



walking, can take place in series also, but the first stimulus 

 in reflex acts comes from without the body ; in automatic 

 acts from the blood. 



FUNCTIONS OF THE CEREBRUM 



562. " There was once a man who, holding out a piece 

 of his own skull, begged for money in the streets of Paris. 



The upper portion of the vault 

 of his skull had been torn off by 

 an accident, and his brain was 

 protected only by the strong 

 fibrous covering of the dura ma- 

 ter. The wound otherwise was 

 healed, and the man strong and 

 well. Now for a small sum the 

 beggar would allow any one to 

 press upon his brain, and when 

 this was done he lost conscious- 

 ness, and, as it were, fell into a 

 deep sleep. But when the pres- 

 sure was withdrawn, conscious- 

 ness returned, and the man 

 awoke. So soon as the blood 

 was squeezed out of the cerebral 

 hemispheres, these organs ceased 

 to work and consciousness van- 

 ished " (Hill). If the blood 

 vessels of the neck are com- 



FIG. 202. -A Sketch to show how pressed SQ as to cut off the Qxy . 



One Set of Nerves takes Messages 



gen from the brain, a person 

 becomes unconscious. If the 

 heart suddenly weakens its ac- 

 tion very much, or if the vaso- 

 motor nerves allow the arteries to lose tone suddenly and 

 increase their capacity for blood, the person faints, from a 



to Certain Centers in the Brain, 

 and how Another Set of Nerves 

 carries Orders from these Brain 

 Centers to the Mouth, the Hand, 

 etc. 



