8 THE POPULAR SCIENCE MONTHLY. 



camping-gear for the Alleghany highlands, and arrange for their re- 

 turn by the end of October. Patrons of a transatlantic passenger- 

 line had better go a month sooner, to avoid the midsummer night- 

 mares of a superheated cabin. European tourists can combine the 

 useful with the agreeable by doing their sight-seeing afoot ; but they 

 should remember that Alpine morning breezes can not always neutral- 

 ize the bedroom air of a South-German tavern, and that sultry heat 

 aggravates the effects of mal-ventilation.* The German, Austrian, 

 and Russian shepherds stay the whole summer with their flocks, but, 

 as a class, are nevertheless remarkably subject to pulmonary diseases, 

 and for the following reason : They pass the night in a Schafer-hiitte, 

 a sort of ambulance-box, eight feet by four, and six feet high, without 

 windows, but with a tight-fitting sliding-door. This door the ill- 

 advised proprietor shuts after dark, and breathes all night the azotized 

 air of his Black Hole of Calcutta on wheels. In the morning he awak- 

 ens with a hacking cough, superadded to a profuse perspiration and a 

 feeling of nausea. The air of the mountain meadows gradually re- 

 lieves the other symptoms, but not the cough, which finally becomes 

 chronic ; and, with exquisite facilities for the attainment of a patri- 

 archal longevity, the slave of the night-air superstition dies in the 

 forenoon of his life. 



Mal-nutrition, combined with a tubercular diathesis, hastens the 

 macerative (or " hectic ") stage of the disease. Air is gaseous food, 

 and the body of an ill-fed man who stints his lungs in life-air is thus 

 suffering under a compound system of starvation. Hence the occa- 

 sional rapidity in the development of tubercular consumption, and its 

 frightful ravages in the homes of the poor, and in the stuffy tenements 

 of French dress-makers and Silesian weavers, where a perpetual air- 

 famine aggravates the want of bread. 



Fat is the best lung-food, and, among all fat-containing substances, 

 fresh, sweet cream is about the best, and salt pork the worst. There 

 is a close correlation between consumption and the various scrofulous 

 affections ; " pulmonary scrofula " is, indeed, sometimes used as a 

 synonym of tuberculosis. The French physiologist Villemin found 



* " The rate of life, and consequently the amount of disintegration, in any organized 

 structure, depend in great measure upon the temperature at which it is maintained ; and 

 thus it happens that the production of carbonic acid from this source, at the ordinary 

 rate of vital activity, is much more rapid in warm-blooded than in cold-blooded animals, 

 and that the former suffer far more speedily than the latter from the privation of air. 

 But, when the temperature of the reptile is raised by external heat to the level of that of 

 the mammal, its need for respiration increases, owing to the augmented waste of its 

 tissues. When, on the other hand, the warm-blooded mammal is reduced, in the state 

 of hibernation, to the level of the cold-blooded reptile, the waste of its tissues diminishes 

 to such an extent as to require but a very small exertion of the respiratory process to 

 get rid of the carbonic acid, which is one of its chief products. And, in those animals 

 which are eapabie of retaining their vitality when they are frozen, vital activity and dis- 

 integration arc alike suspended, and consequently there is no carbonic acid to be set 

 free " (Gurney Smith, " On Respiration "). 



