38 DISEASE AMONG SWINE AND OTHER DOMESnC ANIMALS. 



extent with one or another of the main or principal forms as to malie it impossible to 

 draw distinct lines, have to be looked ujiou as a subordinate form with a lymphatic 

 character. I have been informed repeatedly by reliable persons that in some of the 

 sick animals cutaneous erui»tious have constituted one of the most (conspicuous symp- 

 toms of the disease. If this is a fact, it is possible that yet a fifth form has to be 

 added — erysipelatous. Still I had no chance to examine such a patient, notwithstand- 

 ing I have examined a large number of sick animals, exceediug, I should judge, one 

 thousand. I am, therefore, not prepared to d(!cide whether the cutaneous eruption is 

 a product of the same causes or influences which are at the bottom of the other mor- 

 bid changes, or whether the same is an independent disease, and merely an accidental 

 complication. 



It is probably not necessary to mention that all the morbid changes which have 

 been described as the pi-oducts or attendants of a certain form are but seldom found as 

 a total in one aud the same animal, as some of them are either usually missing or but 

 little developed. Neither will it be essential to state that even the two principal forms 

 of epizootic influenza of swine, leaving the subordinate forms out of consideration, are 

 scarcely ever observed entirely independent of each other or without being in the least 

 complicated with each other; that, on the contrary, the gastric-rheumatic and the 

 catarrhal-rheumatic are not seldom blended with each other to such an extent as to 

 make it very difficult to decide which one has to be considered as the most predomi- 

 nating. In each case the symptoms, too, are blended with each other, and morbid 

 changes, frequently of equal importance, are found in both large cavities, in the chest 

 and in the abdomen. These facts are easily understood by any one who is at all famil- 

 iar with pathology aud with morbid anatomy. The main or predominant character of 

 epizootic influenza of swine is always rheumatic, and the principal seat is in the sys- 

 tem of serous membranes which abound in every large cavity of the animal body. 

 Serous membranes not only line the interior of those cavities, but constitute also the 

 external coat of nearly every internal organ. Hence it is but natural that such a dis- 

 ease localizes itself in many different parts of the animal organism, produces in conse- 

 quence ditferent morbid symptoms, and causes different forms of disease. It is true 

 that in some cases the disease exhibits a prevailing catarrhal character, but if it is 

 taken into consideration that the causes of rheumatic affections and of catarrhal dis- 

 eases are often essentially the same, and that not only the seat but the character of the 

 disorder depends frequently upon an individual predisposition of the animal, a further 

 explanation will not be needed. 



The causes — To ascertain the causes has been my principal object. It was, therefore, 

 necessary to observe a large number of cases, and to investigate the disease in differ- 

 ent localities. This I have done, and have come to the conclusion that at least some 

 of the causes, and I think I make no mistake if I say the most important ones, are of 

 such a nature as to admit removal, notwithstanding they are diverse and numerous, 

 and have their source, to a certain extent, in the manner of farming and stock-raising, 

 or rather hog-raising, customary in the West. Although I will not deny the possibility 

 of an existence of certain agencies of a miasmatic character, nor the possibility of a 

 presence of a micrococci or other microscopic sporules calculated to act as a cause or 

 to contribute in jiroducing the disease, I must confess that if anything of that kind 

 has been acting as a cause, it has escaped my notice. lu the first place I had no micro- 

 scope at my disposal, and secondly I have not been able to discover anythiug in the 

 ■whole morbid process nor any morbid change that caunot be the product of those 

 noxious influences which I consider as the main, if not exclusive, causes of the disease, 

 and which in my opinion are well able to produce every one of those morbid changes 

 which I had an opportunity to observe. Those injurious influences or agencies which 

 I am obliged to consider as the principal causes act in different ways, and, for a better 

 survey, may be divided into three classes. As belonging to the first class I look upon 

 everjthiug that will interrupt or disturb the perspiration. lu the second class I place 

 all such noxious influences and agencies as interfere directly with the process of respi- 

 ration. Fiually, in the third class I put all such noxious agencies or iujurious influ- 

 ences as tend to aggravate the disease if already existing, by aiding in making its 

 character more typhoid, or which produce a siiecial predisposition, by weakening the 

 constitution of the animal. 



1. Injurious influences irhych act as a cause hy producing an inteiTuption or partial cessation 

 of the perspiration. — These influences are numerous, aud of much greater importance than 

 one who looks at them superficially may be inclined to suppose. The skin of an animal 

 is a very important organ ; it not only serves as a protecting tegument, but has also 

 other vital offices which are scarcely of less importance to the existence of the animal 

 organism than those of the lungs. The skin discharges through its pores a large amount 

 of wasted material, and absorbs aeriform and liquid substances from the outside world. 

 Consequently, it may be looked upon as an organ whose duty it is to supplement the 

 functions of several other organs, but espt cially those of the lungs aud of the kidneys. 

 To ascertain the effect which a total interruption of the functions of the skin would 

 have upon the auiiual organism, interesting experiments have been made by Bouley, 



