44 
to L-r will be fomicl in the series. Water is now added to the toxine- 
antitoxin mixtures, so that each flask will contain a total of 4 c. c. 
These flasks are well corked and remain one-half hour at room tem- 
peratme protected from daylight by means of lead shells. After this 
period white mice are inoculated. Corresponding to the mixtures 
made, two series of eight mice each are injected. Each mouse receives 
0.4 c. c. of the particular mixture imder the skin of the right liind foot. 
Each mouse, therefore, receives of an immunity imit plus vary- 
ing amounts of toxine. As the doses of the toxine are selected so that 
each series of eight mice vdll give all values from the L® to the L + 
limits, it is possible to determine from such a series all phases, as some 
animals vdll remain normal, others show symptoms of tetanus, and 
others die acutely. 
If the unknown serum which is being tested has just the strength 
supposed for it in accordance vdth the above test,, then the results in 
the two series of animals correspond precisely. If, however, it is 
weaker, there is a considerable difference in the results; from which 
it is easy to see about how much weaker the serum is than the stand- 
ard serum. The following tables gives an example of tests made in 
accordance vdth the above explanation: 
THE STATE TESTING OF THERAPEUTIC SERA. 
Date : F ebruary 1 . 1905 . 
Tetanus antitoxin: Manuiacturer. X; Xo. y. 
Sent in: January 31, 1905. Eeceived: February 1. 1905. 
Horses Xos. 4 and 6: Bled September 22 and 24. 1904. Quantity of serum sent in: 
5 liters. Phenol content : 0.5 per cent. Strength claimed: 6 X normal. 
Test for sterility: Sterile. 
Test for phenol content: Mouse shoved slight trembling. 
Potency determination: 6 immunity tmits. 
I. Standard serum: Dilution. 0.006 to 26 c. c. 
II. Serum: X Xo. 11. Dilution. 1:600 (=1-1-19. 1+29, etc.). 
III. Xormal poison solution: To 1 c. c. of the diluted serum is added: 
Poison. 
Water. 
0.8 c. c. 
2.2 c. c.=4 c. c. 
0.9 c. c. 
2.1 e. c.=4 c.c. 
1.0 c. c. 
2.0 c. c.=4 c. c. 
1.1 c. c. 
1.9 c. c.=4 c. c. 
1.2 c. c. 
1.8 c. c.=4 c. c. 
1.3 c. c. 
1.7 c. c.=4 c. c. 
1.4 c. c. 
1.6 c. c.=4 c. c. 
1.5 c. c. 
1.5 c. c.=4 c. c. 
The mixture of toxine and serum is allowed to stand half an horn- at room temperature. 
Quantity injected: 0.4 c. c. 
Kind of animal: MTiite mice (15 gi-ams). 
