o2ti THE MODERN HOUSE DOCTOR. 



transpiration. This may be plainly seen by introd «cing phos- 

 phorus into the blood. As soon as the blood containing it 

 arrives at the lungs, it escapes by respiration, the animal breath- 

 ing opaque white vapors, consisting of phosphoric acid, which 

 inflames in contact with air. This continual evaporation is no 

 hinderance to the air coming in contact with the blood circulating 

 through the pulmonary capillary vessels. What is without may 

 pass into the blood, and vice versa. 



" These phenomena command the utmost attention from medical 

 men. It is of the greatest importance to know the composition 

 of the air we respire, since so many diseases are in this manner 

 produced ; and though we with difficulty arrive at any certain 

 knowledge of the miasms rising in marshy grounds, from the de- 

 composition of putrid vegetable and animal matters, there can 

 be no doubt whatever of their entering into the blood, through 

 the medium of the air, and so producing grave disease. In some 

 countries especially, such affections rage with extreme intensity ; 

 in hot, humid climates, and particularly on the sea coast and bor- 

 ders of certain rivers, as, for instance, the Gulf of Mexico, Vera 

 Cruz, New Orleans, &c. Such causes of disease admit of dem- 

 onstration ; since, by introduction of them into the blood, ex- 

 perimentally, may be produced, though not exactly the yellow 

 fever, symptoms bearing the greatest resemblance to it, with 

 black vomit and speedy death. Lower Egypt, where the plague 

 formerly prevailed so alarmingly, owing to such causes, has been 

 rendered comparatively healthy by the improved condition of the 

 country. 



" What we observe in such insalubrious countries and situations 

 abroad as these, is apt but too often to present itself in our dis- 

 secting rooms at home. In spite of every precaution to disinfect 

 such places, and retard the putrefaction of the bodies in them, 

 every year we have a certain number of dissecting pupils seized 

 with the low fever called at the present day typhoid. 



" A very curious experiment has served to show the facility 

 with which miasms enter the blood through the respiratory pas- 

 sages. For a long time it has been the opinion of M. Magendie, 

 that the pulmonary mucous membrane did not extend through 

 the extreme ramifications of the bronchi, — an assertion rebutted 



