424 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



phatic glands were deeply congested, so as to be mottled witli red. The 

 inguinal glands had a In-owuisli-red hue, the sublurabar l.yi))t)hatic glands 

 were enlarged and pigmented. The small intestines presented patches 

 of congestion and redness. The right lung was in greater part red and 

 consolidated. The liver was deeply mottled with inu'ple, and the kid- 

 neys of a very dark red externally. Finally, the spleen was greatly 

 enlarged and gorged with blood. 



Taken all in all, these symptoms are so closely in keeping with those 

 of swine plague that there seemed no reasonable grounds for doubting 

 that it was really this disease. The one drawback to this conclusion is 

 the condition of the spleen ; but the enlarged and blood-gorged condition 

 of this organ is not unknown in the pig itself, as shown in Xo. 1 of the 

 present report. A second reason for not attaching undue importance to 

 the engorged spleen, nor accepting it as indicative of malignant anthrax^ 

 is that the pig inoculated firom this rat developed all the symptoms of the 

 hog-fever, while the spleen was rather shrunken and puckered than en- 

 larged. Had it been inoculated with the virulent products of malignant 

 anthrax, engorgement and distension of the sjDleen had been inevitable- 



SUCCESSFUL INOCULATION FROM THE RAT. 



On February 19 a healthy pig was inoculated with the congested 

 lymphatic glands and lungs of the above-mentioned rat, the morbid, 

 products having been inserted in a pouch under the skin. 



On the sixth day there was much malaise, with redness of the Likiu 

 and the appearance of the black unctuous exudation on the ears and 

 legs. These went on increasing, and black spots and patches, ineflacea- 

 ble by pressure, appeared on the inside of the thighs and hocks. 



The subject was destroyed on the twentieth day and showed the usual 

 symptoms of the disease. The stomach and bowels were congested, with 

 glandular swellings in the large intestines, the lymphatic glands corre- 

 si)onding to the congested bowels were of a deep red, almost black, and 

 elsewhere the lymphatics were enlarged and pigmented. Purple blotches 

 appeared on the Uver, heart, lungs, and air passages, while the Sj^/leen 

 was small, rather bloodless, puckered, and shrunken. 



The symptoms of the disease were, in short, as unequivocal as when 

 inoculation was made from the sick pig direct, and, taken along with the 

 less conclusive evidence furnished by case Xo. 7, may be held to prove 

 that the rat is capable of contracting this disease and of conveying it 

 back to the pig. 



PROBABLE CONVEYANCE OF TSE DISEASE BY RATS. 



In my report for 1878 I expressed an apprehension of this disease be- 

 ing conveyed by rats, which fear is only too fully justified by the more 

 recent developments. The danger of the com^eyance of diseases by these 

 vermin not only from pen to pen, but from farm to farm, can never be 

 lost sight of, as rats do not by any means confine their dei)redations to 

 a circumscribed locality, and are quite ready to emigrate and found a. 

 new colony if their present habitat is unproductive or closely beset by 

 their natural enemies. Rats, therefore, that pass from one piggery tO' 

 another may convey the specific poison on their surface or in their sys- 

 tems, and may not only leave the germs in the troughs while shari ig 

 the feed with the pig, but even inoculate it direct w^hile gnawing th© 

 horns of its feet. 



The importance of exterminating rats from the vicinity of piggeries 



