SERUM THERAPEUTICS. 
491 
The serum employed by Roux and Martin in children and 
guinea-pigs in doses of ^ cc. killed the latter in forty-eight 
hours. Guinea-pigs injected with a quantity of serum equal 
t0 too V oo P art °f their weight resisted a dose fatal to control 
animals in five days; immunized them against a quantity 
fatal in 48 hours. 
Infection having taken place, the quantity of serum nec¬ 
essary to preserve life must be in proportion to the time 
elapsed since the introduction of the poison into the system. 
Guinea-pigs receiving a dose fatal in forty-eight hours sur¬ 
vived after an injection equal to ^ ^part of their weight six 
hours afterwards; the same treatment twelve hours afterwards 
was ineffective. 
This is the principle of the serum treatment of diphtheria 
in children, which in many instances has given such happy 
results. The anti-toxin is not of uniform strength in all cases, 
a fact which explains the alarming and even fatal symptoms 
occasionally seen. 
The dose must be graduated according to the virulency of 
the serum, the weight of the subject and the time elapsed since 
the introduction of the poison. 
The following illustration will show the manner of immun¬ 
ization : Horse, seven years of age, weight 900 pounds. Serum 
very active; ^ cc. killed a guinea pig in forty-eight hours. 
Injected hypodermically in the neck or behind the shoulder. 
1st day, injection of J cc. toxin (^iodine); no reaction, local 
or general. 
2d day, injection of \ cc. toxin (£ iodine). 
4th, 6th and 8th days, injection of J cc. toxin (* 0 iodine). 
13th and 14th days, injection of 1 cc. toxin; (/ 0 iodine); no 
reaction. 
17th day, injection of J cc. pure toxin; slight oedema, no 
fever. 
22d day, injection of 1 cc. pure toxin; slight oedema, no 
fever. 
23d day, injection of 2 cc. pure toxin; slight oedema, no 
fever. 
