6 Cincinnati Society of Natural History. 



medicine thoroughly can by no means ntglect the subject I 

 am about to consider. The different seasons of the year, and 

 what each is capable of affecting, will prove a source of 

 reflection to him. They differ altogether from each other. 

 Diversity exists in their respective constitutions, and even in 

 their individual variations. We study the winds both as to 

 heat and cold. Those that are common to all countries ; and 

 those that are peculiar to certain regions. We ought also to 

 examine the properties of the waters, since all are not alike 

 in taste, or gravity, so neither are they in virtues. Whosoever, 

 therefore, arrives at a town, of which he is not an inhabitant, 

 should begin by regarding its position in relation to the winds 

 and the rising of the sun ; he will not consider it as a matter 

 of indifference, whether its exposure is to the north, the south, 

 the east or the west ; on the contrary, he must have a .strict 

 regard to its position and to the nature of its waters; he must 

 examine whether they are muddy, hard or soft : if they pass 

 through high and stony places ; if of a .saline nature ; and if 

 they sit light on the stomach, and are well adapted for cook- 

 ing vegetables. He should inspect the soil ; and notice 

 whether it be naked and arid, or covered and moist ; if sunken 

 and sultry, or high and air}'. -•'■ * * * Should it be 

 objected that the information which I thus require appertain 

 to meteorology, I reply, that a knowledge of the situation of 

 the heavenly bodies is not one of the parts least essential to 

 form the physician ; on the contrary, it is highly useful. The 

 succession of the seasons is accompanied with remarkable 

 changes in all the cavities of the body." We have here an 

 outline, simply expressed, of the knowledge necessary for a 

 physician to have in relations to weather, water and disease. 

 It embodies the observation of the time and comes down to 

 us with its guarantee for the usefulness of its inculcations. 

 It is observation and not experiment. 



Weather is a product of many complex units. It has its 

 cosmic or world-wide elements, and its telluric or local ones, 

 each of different ])()tentialities. Among the local ones, we 

 may mention the topographic features of land and water and 

 vegetation, which exercise a limited influence comi^arcd with 

 those which have principally their origin from the sun. 



The i)rincij)al factt)rs of weather are atmosphere, with its 



