POLICE POWER 29 
an animal infected with a communicable disease 
may be assessed damages by a court if through his 
negligence the disease spreads to other animals 
of his neighbors.® 
19. Nuisance Per Se, and In Posse. A nuisance 
per se is one which is essentially a nuisance. A 
mad dog is such a nuisance. It should be abated 
without question. A nuisance in posse is one 
which may be a nuisance according to circum- 
stances. A manure pile has a commercial value 
in some communities, and it may exist without 
endangering any person or property. When it is 
located in a city, and is so maintained as to breed 
flies and rats, it becomes in fact or wm esse a 
nuisance, and as such should be abated. A rat 
is always a nuisance per se, and should be extermi- 
nated. An animal infected with a communicable 
disease which is curable is a nuisance, but not 
one per se. As such it may properly be so guarded 
as to prevent the spread of the disease, but the 
officer would not be justified in ordering its de- 
struction, unless its value were insignificant as 
compared with the expense of quarantine. Be- 
cause a nuisance per se is a public danger, it has 
no value, and there can be no property right 
therein. A nuisance im posse has a value often- 
times, and there may be a property right therein 
which must be respected. The building used for 
an illicit liquor traffic is a nuisance in esse; that 
is as used it is a nuisance, but the nuisance is not 
in the building itself, but in its use. The building 
may be put to other uses, and on that ground the 
court might not justify its destruction. 
9 PusLic HEALTH, Chap. VIII. 
