100 DISEASES OF SWINE AND OTHER ANIMALS. 



a serious olistacle to aH attempts to stamp it out. In most of the plagues of animals, 

 and notably in lung fever, in aphthous fever, and in rinderpest out of its native 

 home, the rise of the body temperature iireccdes all outward mauifestations of the dis- 

 ease. In these affections the indications of the thermometer alone enable us to sep- 

 anite the sick anrf healthy before the disease has attained to a stage of material danger 

 to their fellows. But iu the pig fever the earliest symptoms will vary according to 

 the vagaries of the poison and its primary scat of election. Perhai^s the most common 

 initial symptom is the enlargement of the inguinal glands, but it may be some derange- 

 ment of the digestive organs, or it may be the elevation of the body temperature, or it 

 may be the appearance of red spots or blotches on the skin, or finally the poison may 

 bo operating in the system in the absence of all external manifestations. It is notice- 

 able that since the access of extremely cold weather the cutaneous discoloration has 

 been much less extensive than during the warmer season. Even when the tempera- 

 ture has been abnormally raised it will rise and faU in such an irregular manner that 

 no single observation will be always successful in detecting the disease. To detect 

 «uch cases the investigation must be conducted from day to day, and in view of all 

 possible manifestations of the disease, to be successful. Then again the temperature, 

 even in health, varies widely in different swine and under different conditions of life, 

 so that a knowledge of the body heat of the individual in the existing environment 

 is essential to the drawing of sound deductions from thermometric indications. 



INFECTION OF OTHER ANIMAXS THAN SWINE. 



I consider the most important part of my researches to be that which demonstrates 

 the susceptibility of other animals than swine to the fever we are investigating. Dr. 

 Kline of London, England, claimed, nearly a year ago, that he had conveyed the dis- 

 ease "with difficulty" to rabbits, Guinea-pigs, and mice, but he gives no hint as to 

 w^hether he had subjected the question to the crucial test of reinocidation from these 

 animals back upon the pig. This test it seemed very important to apply, so that the 

 identity or otherwise of the two diseases might be determined. I have accordingly in- 

 stituted experiments on a rabbit, two sheep, a rat, and a puppy, the three former ot 

 ■which have turned out successfully. 



INFECTION OF A RABBIT FROM A SICK PIG. 



After two inoculations with questionable results, made with the blood of sick pigs, 

 in which microzymes had been observed, a rabbit was once more inoculated, this time 

 with the pleural effusion of a pig that had died during the previous night, and in 

 ■which were numerous actively mo-ving bacteria. Next day the rabbit was very fever- 

 ish and ill, and continued so for twenty-two days, when it was killed and showed 

 lesions in many respects resembling those of the sick pigs. The blood of the sick rab- 

 bit contained active microzymes like those of the pig. 



SUCCESSFUL INOCUIiATIONS FROM THE SICK RABBIT. 



On the fourth day of sickness the blood of the rabbit containing bacteria was inocu- 

 lated on a healthy pig, but for fifteen days the pig showed no signs of illness. It was 

 then reinocidated, but this time with the discharge of an open sore which had formed 

 over an engorgement in the groin of a rabbit. Illness set in on the third day and 

 continued for ten days, when the pig was destroyed and found to present the lesions 

 of the fever in a moderate degree. 



A second pig, inoculated with the frozen matter wTiich had been taken from the 

 open sore in the rabbit's groin, sickened on the thirteenth day and remained ill for 

 six days, when an imminent death was anticipated hj destroying the animal. Dur- 

 ing life and after death it presented the phenomena of the plague in a very violent form. 



It can no longer be doubted, therefore, that the rabbit is itself a ^^ctim of this disease, 

 and that the poison can be reproduced and multiplied in the body of this rodent and con- 

 veyed back with undiminished virulence to the pig. Wo may follow Dr. Ivline in 

 according a similar sad capacity to the other rodents, mico and Guinea-pigs. Tho 

 rabbit, and still more the mouse, is a frequent visitant of the hog-pens and yards, 

 "where it cats from the same feeding-troughs with the i)ig, hides under the same litter, 

 and runs constant risk of infection. Once infected they may carry tho disease as 

 ■widely as their Avild wanderings may lead them, and communicate it to other herds at 

 a considerable distance. Their weakness and inability to escape, in severe attacks of 

 the disease, will make them an easy prey to the omnivorous hog, and thus sick and 

 dead alike will bo devoured by the doomed swine. 



PROBABLE SUSCEPTIBILITY OF OTHER RODENTS. 



The infection of these rodents creates the strongest presumption tl^at other fjcncra 

 of the same family may also contract tho 4isoaso, and by virtue of an oven closer xola- 



