309 



a great degree dependent upon, accumulations of filth, and impure 

 atmosphere, and that their ravages are immediately under the con- 

 trol of sanitary measures, and may be checked by a faithful com- 

 pliance with proper legislative enactments. 



But these powerful elements of disease do not always present 

 themselves to the consideration of the medical man in forms thus 

 concentrated and fatal. They may occur singly or in subtle forms, 

 requiring great nicety of discrimination, and laboured research to 

 detect them, and under these circumstances, it is impossible for the 

 physician who has not fully acquainted himself with the subject, 

 either to discover or apply the means necessary for their removal. 

 The merest tyro in his profession is enabled to decide upon a strong- 

 ly marked case of disease, exhibiting decided symptoms, but it 

 requires the master of his art to discover through complications 

 which mark the ailment, the true causes of aberration from health. 

 If this be true in relation to the manifestations of disease in the 

 human body, with how much greater force may it not be applied to 

 the discrimination of those subtle agents, which, like the winged 

 messenger of death, float unseen around us, and only manifest 

 themselves in their effects. 



It would be taking an exceedingly narrow view of this subject to 

 confine the operation of these pernicious agents to the production of 

 the two forms of fever already mentioned, or indeed all forms of 

 fever, for there is scarcely a type of disease to which the human 

 body is liable, that may not be directly induced, or at least sus- 

 tained by them, and perhaps the evil influences exerted by the indi- 

 rect action of these deleterious causes, are more to be dreaded than 

 those more direct and fatal. When not sufficiently concentrated to 

 produce fever, they may act by deranging the function of one or 

 another of the organs of the body, and thus destroy its power to 

 resist disease from other sources. Disorders of the digestive organs 

 sufficiently numerous in themselves, occasioned by these causes, by 

 enfeebling the body, render it susceptible to alternations of tempe- 

 rature, and thus death occurs from inflammation of the air-tubes, 

 consumption, and kindred causes. It is scarcely possible to esti- 

 mate the amount of mortality thus induced by the indirect action 

 of these poisonous agencies. 



In view of the immense and growing importance of this subject, 

 the Medical Department of the National Institute would recom- 

 mend to the American Medical Association— 



