SERO-THERAPY 211 
have from time to time been produced, tested, and pro- 
claimed infallible by their promoters, yet many users have 
pronounced against their efficacy. In any case they can 
do little harm, but may on the other hand do considerable 
good, and I unhesitatingly recommend a trial, having 
first obtained what is considered the best available pro- 
duct. 
The latest, and therefore probably least known, serum 
is that of Ferry, which is obtained from the blood of 
animals that have been immunised against several strains 
of B. bronchisepticus. This serum may be given at any 
stage of the disease in doses of 5 c.c. daily, or, if the case 
is severe, twice daily. Ferry states that in the early 
stages doses of serum may be alternated with doses of 
vaccine with very good effect. 
Polyvalent antistreptococcic and antistaphylococcic 
sera are now obtainable, of canine origin, which should 
have a marked salutary effect when employed against 
secondary infections, for we know that in nearly every 
fatal case it is the complication and not the primary 
infection which directly brings about death, and that the 
causal organisms of these complications are frequently 
cocci. 
However, since Ferry’s mixed bacterin contains B. 
bronchisepticus, staphylococci, and streptococci, it follows 
that if an animal is immunised with this bacterin, the 
immune serum obtained from that animal’s blood should 
possess antibodies which would not only neutralise the 
toxins of B. bronchisepticus, but also those of the cocci 
named ; and this property is a distinct advance on all 
previous sera, which have never exerted any influence 
whatever on secondary infections. 
