26 DISEASES OF SWINE AND OTHER ANIMALS. 



■winch can be repaired but slowly or not at all — remain behind, and inter- 

 fere more or less ■with the j^Towth and fatteninjr of the aniim'.l. 



From a ijccuniaiy standpoint, it makes but little dih'erence to the 

 owner whether a pig affected Avith this plague recovers or dies, because 

 those -wliich do siu-vive usually make very x)oor returns for the food 

 consumed, unless the attack has been a very mild one. 



4. MOKBID CHANGES. 



The morbid i)roeess, although everywhere essentially the same (see 

 chapter on Contagion, Causes, and Nature of IVrorbid Process), can have 

 its seat in many different organs or jiarts of the body, and produces, 

 therefore, a great variety of morbid changes. The disease, in conse- 

 quence, very often presents a somewhat dift'erent aspect in difierent 

 animals. In some cases the i^rincipal seat of the morbid process is in 

 one organ or set of organs (organs of respiration and circuhition, for 

 instance), and in others in entirely different parts (intestinal canal and 

 organs of digestion, &g.) Death, therefore, has very often a different 

 cause in different cases; in some cases it results from a, cessation of the 

 functions of the heart, the lungs, «S:c., and in others it is in consequence 

 of the inability of entirely different organs to perform their functions, 

 — of the digestive apparatus, for instance. 



But fe'w morbid changes have ever been found entirely absent at any 

 of the fifty-three post-mortem examinations made since August 2, and 

 may, therefore, be considered as a constant occurrence. All others have 

 been found absent a. larger or smaller number of times. These constant 

 morbid changes consist — 



1. In a more or less i)erfect hepatization of a larger or smaller portion 

 of the lungs, or a more or less extensive accumulation of blood, blood- 

 serum and exudation in the pulmonal tissue. In some cases the morbid 

 changes (hepatization) found in the lungs are so extensive as to cause 

 the latter, if thrown into water, to sink like a rock, but in other cases 

 the hepatization is limited to about one-sixth or one-eighth of the whole 

 pulmonal tissue. In some cases, especially those in which the morbid 

 changes were of a recent origin, no real hepatization, fully developed, 

 had yet been effected ; the lungs were merely gorged with exudation or 

 blood-serum; the texture was not yet destroyed or seriously changed, 

 but innumerable small red spots or specks, indicating incipient embolism, 

 were plainly visible to the naked eye. (See photograph, Plate I, half-size 

 lungs, right side of experimental pig No. VJI, and photograph, Plate II, 

 enlarged section of same lungs.) In other cases a part of the exudation 

 had changed, organized, or become a part of iXw tissue, and had caused 

 the latter to become more or less perfectly impermeable to air. In some 

 lungs hepatization was found only in certain insulated places, while in 

 others the hepatization extended uninteri-uptedly over whole portions. 

 In all these cases in wliich the hepatization v/as very limited, it was found 

 principally in the anterior lobes. In some animals (that is in those which 

 had been sick for some time), old or so-called gray, more recent or brown, 

 and very ucav or red he]>atization were frequently found side by side, or 

 in more or less distinctly limited patches, showing jdainly that the morbid 

 changes had not l)een producecl at once, l)ut at several internals. In 

 others, usually the upper ])arts of the same lungs, the exudation ov blood- 

 serum had I )een recently deposited, and was yet in a fluid cond ition. The 

 blood-serum, examined under tlie microscope, invariably contained, be- 

 sides blood-cori)nscles, numerous /^r/f'j///.s»/,s', some moving and some with- 

 out ujotion, and innumerable bacillus-germs, of which some had budded, 



