114 TWENTIETH ANNUAL REPORT OF THE REGENTS. 



SANITARY CLIMATOLOGY AND ITS RELATIONS. 



Humidity, heat and cold are the sources from which are produced most 

 of the diseases lying within the geographical limits of the Northwestern 

 States. From what observations have been made, the sanitary division of 

 diseases indigenous to the above region might, with propriety, be classified 

 as follows : 



1. Malarious and L,on-inflammatory diseases, with their associated epi- 

 demics, reaching to the 44th" or 45th° of north latitude, with the summer 

 isothermal of 60°. 



2. Pulmonary and inflammatory diseases, with their associated epidemics, 

 extending southward to the 30tli° of north latitude, and winter isothermal 

 of 50°. 



All diseases ranging under these classifications, in all degrees of violence, 

 are observed each year l)y physicians who are called upon to treat them, 

 and who find that they have an intimate physical relation with the seasons, 

 as the isothermal line moves from the South to the North in the spring and 

 early summer, and as it recedes to the South again in the autumn and winter. 



Beginning near the middle of June until the middle of October, all dis- 

 eases appear to be more or less of a malarious character, and their violence 

 attends a high atmospherical temperature and humidity ; and from that time, 

 or about the first of December, until the following April or May, pulmo- 

 nary and inflammatory diseases principally exist, on account of the low 

 temperature and moisture of the atmosphere. These phenomena in the 

 movement of the isothermal upon diseases are a constant attendant in our 

 sanitary climatology, and is the physical law which seems to goyern dis- 

 eases that are subject to climatic influences. 



Perhaps no subject opens itself for investigation to the intelligent phy- 

 sician a more pleasant study than this of the Greographical Limitation of 

 Disease. Like the studies of Natural History, the foundation upon which 

 rests the beautiful structure of the medical art, it each day presents some- 

 thing new and interesting within the thought and observation of its most 

 humble student; and could each one take and reduce sanitary observations 

 to a system, it would be a source of gratification to himself, and his record 

 of disease and mortality, when compared with others, would be one of the 

 links needed in the statistics of a Sanitary Climatology. 



