9 
is taken because it is very convenient in measuring out the test 
dose, which represents 1 c. c. of the solution. Thus: 
44. 5692 gm., bottle + toxine. 
44. 5300 gm., bottle. 
. 0392 gm., toxine. 
0.1 gm. : 166.66 c. c. :: 0.0392 ; x. 
X = 65.33 c. c. 
In other words, if the quantity of toxine placed in the weighing 
bottle should weigh, as in this instance, just 0.0392 gm., carefully 
deliver from an accurately graduated burette just 65.33 c. c. salt 
solution into the weighing bottle; and, as before stated, each cubic 
centimeter of this solution will be the L + or test dose. 
Now dissolve the serum of unknown value in accordance with the 
table of dilutions (page 50) and mix aliquot parts of the serum with 
the test dose of toxine, as follows: 
Table No. 1. 
No. of 
guinea 
pig- 
Weight of 
guinea 
pig 
(grams). 
Subcutaneous injection of 
a mixture of — 
Time of death. 
Toxine (test 
dose) . 
Antitoxin. 
1 
3G0 
Gram. 
0. 0006 
c. c. 
0. 001 
2 days, 4 hours. 
O 
350 
.0000 
.0015 
4 days, 1 hour. 
3 
350 
.0006 
.002 
Symptoms. 
4 
300 
.0000 
.0025 
Slight symptoms. 
5 
350 
. 0006 
.003 
No symptoms. 
According to this series the guinea pig which received 0.0015 c. c. 
of the serum died in four days and one hour. Therefore 0.0015 c. c. 
of the serum contains one^tenth of an immunity unit, as the unit has 
been defined as ten times the least amount of antitetanic serum neces- 
sary to save the life of a 350-gram guinea pig 96 hours against the 
official test dose. This serum would, therefore, contain just 66 units 
per cubic centimeter. 
On account of the importance of the L+ or test dose the following 
table is given showing the results of these tests with Toxine A. 
T^ble No. 2. — Showing the results of the test (L-\-) dose of tetanus toxine A from Janu- 
ary 17, 1907, to April 7, 1908. 
Guinea pig No. 
Weight 
in grams. 
Date. 
Amount of 
toxine A. 
Amount of 
antitoxin. 
Time of 
death. 
306 
290 
Jan. 17,1907 
Gram. 
0. 0006 
1 unit 
Days. Hours. 
4 0 
326 
300 
Jan. 24,1907 
do 
.0006 
1 unit 
3 3 
334 
315 
.0006 
1 unit 
3 7 
387 
350 
Feb. 20,1907 
.0006 
1 unit 
4 19 
388 
350 
do 
.0006 
1 unit 
4 8 
389 
350 
do 
.0006 
1 unit 
4 16 
