116 ANNUAL REPORT OF THE Off. Doc. 



Philadelphia. All of these horses belonged to different owners 

 except four, which were the property of one man. Fourteen cases 

 occurred in Lancaster county. All of these horses were the prop- 

 erty of one firm, having 35 horses. Some of the horses of this firm 

 were afflicted with glanders while they were in Maryland and before 

 they were brought into this State. All of the infection in this out 

 break appears to go back to this source. Eleven cases occurred in 

 Beaver county. AH but one of these horses belonged to one firm 

 having, altogether, about fifty horses. Nine cases occurred in 

 Cambria county among a large number of mules that belonged to a 

 company engaged in coal mining. 



A number of horses that have reacted to the mallein test are still 

 in quarantine at the end of the year, and are being held for the 

 re-test. These horses show no symptoms of glanders and, although 

 they have reacted to the mallein test their destruction is not 

 ordered, because it has been found in some cases that horses in the 

 very earliest stages of glanders may safely be kept alive and re- 

 tested, and that in some such cases the disease appears to recede 

 to such a point as to constitute recovery. This, however, is not 

 believed to occur in any case, at least in this country, where the 

 disease is so advanced as to have led to the occurrence of external 

 symptoms. Where a horse reacts to the first test with mallein 

 and fails to react upon three subsequent tests, with increasing 

 doses of mallein, the tests being not less than a month apart, and 

 if the horse during all this time is in good physical condition and de- 

 velops no symptoms whatever of glanders, it is believed that it may 

 safely be released from quarantine. If, however, the horse continues 

 to react to mallein, this is taken as evidence that the disease is not 

 receding, but that it is continuing in a more or less active form, 

 and that the horse cannot safely be released from quarantine. This 

 procedure has been followed in dealing with glanders for a number 

 of years and thus far it has given satisfactory results. A large 

 number of horses that have reacted once to the mallein test and 

 that have subsequently failed to react have been released from 

 quarantine and have been kept under observation for several years. 

 They have not developed glanders nor have they transmitted glan- 

 ders to other horses, so far as it has been possible to determine. 

 It is evident, however, that this procedure can be safe only with 

 relation to horses that have very recently acquired infection and 

 then, probably, only in minimum quantity. If hypersensitiveness 

 to mallein continues on successive tests, it is not believed that 

 it is safe to take chances. 



Such cases, may, however, appear to be rather difficult to adjudi- 

 cate. A horse seemingly in perfect physical condition may have re- 

 acted to the mallein test two or more times. The horse shows no 

 symptoms whatever of glanders but the mallein tests shows that 

 he is afflicted. The owner of such a horse will sometimes protest 

 strongly against having an animal destroyed or against it being 

 kept in quarantine. It is, of course, possible that such a horse may 

 safely be worked for a long time, and that for many months the 

 disease may not develop to such a point as to enable this horse to 

 transmit disease to others. Indeed, it is conceivable that in some 

 rare cases (although it is not proven) the disease may remain sta- 

 tionary in such a subject and that during its whole natural life it 



