INFLUENZA IN HORSES. 241 



at half past 2 forty men were suddenly attacked with influenza ; at 6 

 o'clock sixty men were ill, and by the next day one hundred and sixty. 

 The instances of Admiral Kempenfeldt's and Lord Howe's squadrons, 

 attacked while cruising at different parts of the same channel, in 1782, 

 after they had been from twenty-two to twenty-seven days at sea, are 

 no more difficult to explain. Indeed, the fact that a squadron had been 

 technically a number of days at sea is no proof that officers and men 

 had not availed of their near proximity to pay frequent visits to the 

 shore. 



Pathology. — Influenza has been thought to be a simple catarrhal 

 disease, with a special prostrating or debilitating tendency, because of 

 some unknown condition of the atmosphere, or something else vaguely 

 referred to as epidemic influenza. Some color was lent to this by the 

 irregular and sometimes dangerous course of the disease occurring during 

 an influenza epizootic. But this influencing of other diseases is common 

 to other epizootics the specific nature of which is unquestionable. 

 During the cholera epidemic, for example, not only men but animals 

 show a special imtability of the digestive organs and tendency to 

 diarrhoea. In marshy regions nearly all other affections are modified in 

 character and com-se by the malarious poison, and, indeed, the history 

 of influenza is that of a disease propagated by a specific poison, and 

 advancing in the face of all circumstances and obstacles, and entirely 

 independently of tliose conditions which cause the development of 

 catarrhs. 



That a specific poison exists is fiiirly established by an impartial re- 

 view of the .epizootic of 1872. But this poison does not produce in all 

 cases the same lihenomena. The symptoms of nasal catarrh are the most 

 constant, but they are often slight, and, at an early stage of the disease, 

 even overshadowed or superseded by those of intestinal catarrh or 

 rheumatism ; and if the poison may thus localize itself in unusual situa- 

 tions without apparent cause, how much more likely if some organ, or 

 system of organs, is already the seat of disease and consequent weakness 

 and susceptibility. 



The theory of the existence of a fungus, which multiplied in the 

 atmosphere, or in the diseased body, or in both, has long been a favorite 

 one, and would fully explain the phenomena of the disease and its pro- 

 gress. But no such fungus has been found, and those found in the more 

 northern part of the continent differ from those found in the south. 

 They are moreover found in great abundance in the dust of fodder, and 

 as plentifully after the disease has long passed as during its prevalence. 

 This doctrine is therefore at present in want of facts to "sustain it. The 

 only other tenable hypothesis appears to be that of a true contagium. 

 Particles of the living body (granules or bioplasm) are given off' in 

 myriads, are carried widely by the air, and infect other animals. 



How, then, does such poison operate"? Hertwig's experiments seem to 

 show that it is not conveyed from animal to animal by the transfusion 

 of blood, and cannot therefore be present in the circulating fluid. It 

 would foUow that the various nervous, rheumatic, and cardiac symptoms 

 were produced by nervous sympathy, owing to the presence of the poison 

 on the mucous membranes, or by the absorption of some noxious products 

 formed in the mucous membrane by reason of its presence. Yet this 

 fails to exi^lain satisfactorily the early and profound prostration before 

 the poison could be developed to any extent on the mucous membrane, the 

 extreme weakness and inability for active exertion which remains after 

 the animal has apparently recovered, and the liability to one or other 

 of the dangerous complications which exhaustion or maltreatment at 

 16 A 



