CHAPTER VI. 



THE NERVOUS SYSTEM. 



The progress of knowledge of the nervous system has been very- 

 slow. Most of the other viscera were known to the ancients before 

 the brain was recognized. The word "brain" is not to be found in the 

 Bible. The ancient Hebrews evidently looked upon the heart as the 

 seat of the soul. The kidneys were the habitation of the mind, while 

 the tender emotions were referred to the bowels. Plato was perhaps 

 the first to assign the supreme seat of the mind to the brain, but his 

 views were purely speculative, inasmuch as he confounded the sub- 

 stance of the brain and of the spinal cord with the marrow of bones. 

 Aristotle, about 335 B. C, examined the brain for himself and con- 

 cluded that its function had nothing whatever to do with the mind, 

 but that it was a refrigerating organ which cooled the blood for the 

 heart. He reasoned according to the knowledges of his time. The 

 brain was apparently an insensible and inexcitable organ as contrast- 

 ed with the heart, which is the opposite. Hippocrates recognized how 

 soon animals became unconscious from the loss of blood, or how 

 changed by blood poison or by the heated blood of fever; hence the 

 inference by Aristotle that the conscious mind resided in the blood 

 and that the great central organ, the heart, was the seat of the soul. 

 The arteries (from the etymology, air tubes or wind pipes) found 

 empty after death, were supposed to carry air or ^^ethereal" spirits to 

 the rest of the body. It was this great blunder that delayed for cen- 

 turies, virtually until Harvey's time, all progress of knowledge of the 

 true function of the heart. Hippocrates maintained that the brain 

 was a gland. With this supposition subsequent writers ventured the 

 suggestion that the brain secretion was a subtile fluid which they 

 designated "animal spirits.** The authority of such names as Hip- 

 pocrates and Aristotle forbade first hand investigation for fully five 

 centuries. It must not be overlooked, however, that amid all this 

 guessing, Alcmaeon (about 500 B. C), an anatomist and physiologist, 

 taught that the brain was the seat of the mind and that all sensation 

 traveled to the brain by means of the nerves. He spoke of the nerves 

 as "tendons" which misconception held sway until Descartes, the 

 philosopher, showed the difference between tendons and nerves. 



About 300 B. C. sprung up the Alexandrian school of anatomists 

 and physiologists of whom Herophilus and Erastistratus were chief 

 who dissected the brain and traced to it the nerves as Alcmaeon had 

 done. They even went so far as to distinguish nerves of sensation 

 and nerves of motion, but were still hampered by Alcmaeon's "ten- 

 dons." "When Greece fell under the subjection of Alexander, mind went 

 into exile, and its first asylum was the city of the conqueror." Under 

 royal patronage the study of anatomy and physiology and surgery 

 made great progress. Galen spoke of Herophilus and Erastistratus as 

 possessing more accurate knowledge of the human body than any one 

 before their time. Herophilus was the first anatomist of importance 

 in the annals of medicine. He is said to have discovered the lacteal 



