218 AGRICULTURAL REPORT. 



tions of blood in tlie limbs and beneath the skin in various parts char- 

 acteristic of innjmra Jucmorrhagica. 



Causes of the influenza. — Unlike the majority of former epidem- 

 ics yrhose origin has been obscure, this appears to have sprung into ex- 

 istence in the center of the Xorth American continent, and in a dis- 

 tinct locality, which can be definitely pointed out. It has spread 

 rapidly and steadily in nearly ever^^ direction, from this as a center, 

 [ind, thanks to facilities aiforded by railroads and telegraphs, its course 

 has been traceable "with ease. The following is intended as a contribu- 

 tion toward securing the lessons which may be learned from the visita- 

 tion. 



The old doctrine of an epidemic constitution of the atmosphere has 

 of lato years been gradually waning, as cholera, small-pox, typhoid 

 fever, and other epidemics and epizootics have been traced to more 

 tangible causes, and placed more under human control. More than any 

 other epidemic malady, jierhaps, has influenza retained its claim on an 

 atmospheric causation. It has been described as falling simultaneously 

 on all parts of a given district or country, as breaking out in islands a 

 considerable distance from the shore, and without having had any com- 

 munication with the main-land, and as ha\ing attacked the crews of 

 ships in mid-ocean after they had been twenty days at sea. !N"o wonder 

 that we should have had all imaginable general conditions of the earth, 

 water, and air invoked to explain its occurrence ; that at one time it 

 has been attributed to the lowness and damimess of a locality; at 

 another to the height, exposure, and coldness ; at a third to crowding 

 of population with the resulting impurities of soil, water, and air; in a 

 fourth case to the vicissitudes of weather in late spring, autumn, or 

 winter, or of some unusually variable season ; to a persistent low tem- 

 perature, or sudden A^ariation of temperature; to the prevalence of 

 damps, acrid or fetid fogs, and mists ; to excessive rain-fall and unusual 

 humidity of the atmosphere ; to an unusually high or low density of the 

 atmosphere ; to an excess of ozone in the air; to the telluric emanations 

 attendant on great earthquakes and volcanic eruptions, or to a modified 

 condition of the atmospheric electricity. 



The epizootic of 1872 affords but the slenderest appearance of support 

 to any of these hypotheses. Neither soil nor elevation has materially 

 affected it. The prevalence and mortality have been almost the same 

 in the mountains of Vermont and New Hampshire as in the flat, mala- 

 rious sea-coast of New Jersey, Maryland, and Virginia. The district 

 where it originated, according to the report of Professor A. Smith, is 

 very variable. In the township of York, near Mimicu, Canada West, it 

 is partly " heavy clay and partly a sandy soil, intersected with swamps- 

 In another part of the township of York the soil is formed of clay, inter- 

 mixed with sand, and the subsoil generally is not porous. In Scar, 

 borough and Markham the land is good and the farms well cultivated, 

 the buildings, stables, &c., generally comfortable and well ventilated, 

 and the horses well fed, and otherwise carefully attended to." 



T;io temperature has not exerted any marked influence. The disease 

 has been general wherever it has reached, and the mortality has aver- 

 aged 1 per cent, or a little over. Indeed, in some cases the comparison 

 has been altogether in favor of the more northern and colder localities. 

 Thus in Fulton County, Georgia, it is reported as universal, and the 

 mortality up to the date of the report had been 1 per cent. ; in Dodge 

 County, Wisconsin, on the other hand, although, after the outbreak of 

 the affe(!tion, there had been a sudden transition in a single night from 

 u pleasant Indian summer to the rigorous and persistent cold of win- 



