70 ARTIFICIAL INSANITY. 



which are experimentally produced for the purposes of phy- 

 siological and pathological study have at least the high aim 

 of improving man's knowledge of the natural history and 

 treatment of disease, mental and bodily. The comparative 

 pathologist, physiologist, or psychologist cannot justly be 

 accused either of ignorance or of wanton cruelty. All his 

 experiments are determined by definite and humane purpose, 

 though this purpose is not at all likely to be understood by 

 the general public. 



In certain animals idiocy can be easily produced by various 

 artificial lesions of the cerebral substance. Thus the Swiss 

 physiologist Gudden has proved that < removal of the cerebral 

 hemispheres of the young animal is followed by idiocy in the 

 adult.' He found also that, when both eyes of a pigeon 

 were enucleated soon after it was hatched, ' the bird grew up 

 in a condition of idiocy.' 1 Dr. Fothergill, of London, informs 

 us that ' in Dr. Terrier's experiments on monkeys, irritation 

 of the occipital lobes (of the brain) produced marked symp- 

 toms of melancholia.'* 



Section of the sciatic nerve in the guinea-pig, according 

 to Brown -Sequard, gives rise sometimes to c loss of conscious- 

 ness, and a state of torpor, stupidity, and even, in a few 

 instances, insanity for a while, after the attack 'of convul- 

 sions produced or determined by tickling or gently pinching 

 the skin. 3 



Terrier found rage one of the results of electrical stimula- 

 tion of the brain in some of the animals on which he experi- 

 mented. 



A great variety of morbid mental phenomena may be 

 produced by the administration of narcotic, irritant, or other 

 poisons animal, vegetable, and mineral in certain forms 

 and doses, including the following : 



1. In the solid or fluid state- 

 Alcohol. 

 Chloral. 



1 Eeview of Recent Eesearches on the Physiology of the Nervous System, 

 by Professor McKendrick, of Glasgow, 1874, pp. 34-5. 



2 British Medical Journal,' December 26, 1874, p. 817. 

 8 'Lancet,' January, 1875, p. 8. 



