364 Human Physiology. 



the lungs, the mesenteric glands, and other organs, and form 

 tuberculous deposits. 



The diseases of the brain and nervous system are generally 

 -diseases of nervous disorder and exhaustion. The brain is 

 Tvorn with labour and care, excited and therefore weakened 

 toy stimulants, exhausted by amative irregularity and excess. 

 Hysteria, chorea, and epilepsy are generally connected with 

 excitement and exhaustion of the generative system, with ama- 

 tive passion and unnatural or excessive gratification. Tobacco 

 poisons the nerves of organic and animal life; tea and coffee 

 excite and disorder them; alcohol, absorbed into the circu- 

 lation, penetrates the brain, and disorders and impairs all its 

 functions. Drunkenness is a mania, and the habitual drunkard 

 has little more power of self-control than any other lunatic, 

 .and as much needs restraint and proper treatment. Drunken- 

 ness should, in fact, be considered and treated as a disease, 

 .and the drunkard kept out of the temptation and the possibility 

 of indulging his morbid appetite, either by removing him from 

 drink or drink from him. 



The diseases of the heart and circulation are those of 

 nervous exhaustion and bad nutrition. The latter may depend 

 upon the former in a diminished power of digestion and assi- 

 milation, or upon unhealthy food, or deficiency, or excess. 

 The use of stimulants acts very directly upon the blood and 

 the organs which contain it ; while the more virulent poisons 

 of strong coffee, tea, and tobacco excite, and then paralyse the 

 nerves which control the action of the heart. 



The distinguished German chemists, Dr. Aubert and Dr. 

 Haase, obtained 8 or 9 per cent, of caffein from coffee, and 

 from 2 to 2^ per cent, of an almost identical element from the 

 best Pekoe tea. It causes reflex nervous excitability and 

 tetanus, acting on the nerve centres, and producing effects 

 resembling those of strychnia. A frog is tetanised by the five- 

 vihoiisandth part of a gramme, and a cat or dog by one-fifth 



