ATMOSPHERE IN RELATION TO HUMAN LIFE ANT HEALTH. 335 



harmless to wounds, except, no doubt, in certain unhealthy situations 

 and near the ground. This conviction agrees well with the realization 

 by physiologists and by public health departments of the general rule 

 that epidemics exist through the action of man and not of the atmos- 

 phere. "It is in the power of man," in Pasteur's opinion, "to cause 

 the parasitic maladies to disappear from the face of the globe if, as I 

 am convinced, the doctrine of spontaneous generation is a chimera." 



The effect (1) of temperature and (2) of moisture in promoting the 

 growth of various kinds of mold, fungi, saccharomycetes, and plant 

 parasites. Ordinary mold seems to grow well at a low temperature, if 

 the moisture be sufficient. 



The influence of dry air in weakening various kinds of microbes or 

 fungi in relation to plant and animal diseases. Their growth on various 

 fomites in relation to qualities of the air and to light. 



The relation of weather to diseases, not only to those apparently 

 caused by microorganisms, but to a variety of other maladies. A cer- 

 tain climate or a certain kind of weather may give rise to an excess or 

 maximum of a spreading disease by direct influence on the outside 

 growth of a microbe, or by helping to spread the spores or germs, or by 

 increasing the supply of some pabulum, or by effects on wells and water 

 supply, or by affecting the human constitution so as to lay it open to 

 attack, or by producing effects on human conduct which favor the 

 spread of the disease. The contributory factors may be many, remote, 

 or concealed, but such thorough investigation as is possible could 

 hardly fail to give valuable results. 



There is generally a main cause in each disease by attacking which 

 much progress is made. The soil temperature in diarrhea and cholera, 

 the dried sputum in consumption, the close air in typhus, have already 

 been thus marked out. 



The lesions, or quasi-lesions, by cold and chill, are exceedingly effect- 

 ive in disarming the resistent powers of the body, so as to give oppor- 

 tunity to such diseases as bronchitis, pneumonia, liver and kidney 

 diseases, dysentery, malaria, and many others. The manner in which 

 by clothing and otherwise these consequences of atmospheric variations 

 may be guarded against might well form a subject for research. The 

 rate of cooling of vessels at the blood temperature surrounded by 

 various fabrics would give useful information. Some experiments of 

 Mr. Garrod 1 showed that in a room at about the average annual tem- 

 perature of the exterior air, when clothes are removed from the human 

 body, the temperature very quickly rises in the axilla to a point 2° 

 higher than before. The blood vessels are of course congested, and 

 colds, etc., are then easily caught. The rise does not take place when 

 the temperature of the room is above 70° F., and increases as the 

 temperature of the air is less. 



» Proc. Roy. Soc, 1869, No. 112. 



