Human Physiology. 



deaf, blind, idiotic, deformed. Worse, they are born with here- 

 ditary predispositions to vice and crime. So that birth, or 

 hereditary predisposition, is one of the most fertile and fatal of 

 all the causes of disease. Whole families die of consumption, 

 inherited from consumptive parents. Diseased parents beget 

 diseased offspring. Short-lived parents have short-lived chil- 

 dren. A certain portion of our diseases are thus made for us 

 by our progenitors. We have therefore not only to struggle 

 against and endeavour to subdue the diseasing conditions 

 around us, but to combat and, if possible, eradicate these 

 hereditary taints, predispositions, and idiosyncrasies. 



Reverse the conditions of health, and we have the causes of 

 disease. For light, have darkness or deep shade and gloom, 

 and you shall see palor, a feeble circulation, a low vitality, 

 tuberculous disease, scurvy, goitre, blindness, deafness, defor- 

 mities, idiocy, a miserable life, and a premature death. Thick 

 curtains will give a fashionable palor to the complexion, and 

 they will also give many fashionable diseases. 



If pure air, fresh and vital, electric and ozonic, be necessary 

 to health, air impure, stagnant, dead, exhausted of oxygen, 

 loaded with carbonic acid, or noxious gases, or vegetable or 

 animal impurities, must be a cause of disease. The blood 

 demands a certain amount of oxygen every moment; and the 

 nerves of organic life demand also in a pure and vital air their 

 natural food and stimulus. What it is, chemistry does not tell 

 us ; but we feel a glow, an exhilaration, in the fresh air of the 

 mountains or the sea-shore that we never find in the effete, 

 dead, loaded, and often noxious air of towns. 



What the air may be as a cause of disease what it may 

 carry of diseasing matter or diseasing force we know in malari- 

 ous and contagious diseases. A few days' exposure to the 

 atmosphere of a fever and ague district will produce an inter- 

 mittent fever that may last for months or years. One night in 

 an American rice swamp, or an East Indian or African jungle, 



