Human Physiology. 367 



they contain, but from what they lack. Fruit, greens, like 

 .spinach, brown bread, and especially coarsely ground wheat 

 mush or porridge, produce a full, easy, and regular action of 

 the bowels. The cause of constipation would, therefore, seem 

 to be in many cases the lack of a certain proportion of innutri- 

 tious matter, or woody fibre, which is contained in the natural 

 food of man eaten in its natural condition. When horses are 

 deprived of hay, straw, husks, &c., they become constipated, 

 and instinctively eat their mangers, wood shavings, and even 

 their blankets, to get the coarse matter they require. 



Poisons, vegetable, animal, and mineral, are causes of dis- 

 ease. Some vegetable poisons, eaten by accident, sicken or 

 kill. All the narcotics are poisons, killing in large doses; 

 injuring, assuredly, when taken habitually even in moderate 

 doses. It will not be pretended that opium-eating is not 

 injurious. Tobacco is as poisonous as opium. A concen- 

 trated dose kills as surely. The same is true of tea and coffee. 

 The injury all of them do to the nervous system is evident in 

 snany cases; but the fact remains that they are all, even inclu- 

 -ding opium, habitually used by many through a course of years 

 with no very marked injurious result. Habit is a second nature, 

 and enables people to tolerate, and seem to thrive, on arsenic. 

 And we have this difficulty in regard to all drugging and medi- 

 cation : we cannot compare the actual case of the patient 

 with what it would have been under other conditions. We 

 can only judge by experience and general principles. 



Of animal poisons we have examples in stings, the bites 

 of poisonous reptiles, poisons developed in putrifying flesh, 

 glanders in horses, with which men are sometimes fatally 

 inoculated, hydrophobic virus, gonorrhoea, syphilis, small-pox, 

 and vaccine matter, which sometimes carries with it the matter 

 of other contagious diseases. All these poisons may be the 

 causes of annoying, severe, and fatal diseases, and for some of 

 them medicine has found no remedy. 



