634 ANAPHYLAXIS IN RELATION TO INFECTION AND IMMUNITY 



(6) The diluent is sterile 0.8 per cent, salt solution with 0.25 per 

 cent, pure phenol. This is readily prepared by adding 8 grams of 

 pure sodium chlorid and 2.5 c.c. of pure phenol to 1000 c.c. of distilled 

 water. Dissolve, and filter into one large Erlenmeyer flask or, prefer- 

 ably, into ten smaller flasks. Sterilize in the Arnold sterilizer for one 

 hour, or in the autoclave for twenty minutes, or by gently boiling for 

 fifteen minutes on each of two consecutive days. 



(c) Into each bottle place 9 c.c. of the diluent with a graduated and 

 sterile pipet. Bottle 1 contains pure tuberculin. To bottle 2 add 1 

 c.c. of tuberculin and shake carefully; to bottle 3, 1 c.c. from bottle 2 

 and shake; to bottle 4, 1 c.c. from bottle 3 and shake; continue in 

 this manner to bottle 8, from which 1 c.c. is discarded. 



(d) We now have the following dilutions : 



No. 1 pure tuberculin. 



No. 2 0.1 c.c. tuberculin in each cubic centimeter. 



No. 30.01 c.c. " 



No. 40.001 c.c. 



No. 50.0001 c.c. 



No. 60.00001 c.c. 



No. 7 O.OQ0001 c.c. 



No. 8 O.OOQOOO,! c.c. 



(e) These dilutions are usually prepared every two weeks. When 

 not in use, the bottles are kept in a cool, dark place. It may not be 

 necessary to prepare all dilutions. For example, dilutions No. 3 and 

 No. 4 are sufficient for diagnostic purposes, as 0.1 c.c. of No. 4 equals 

 0.1 mg. of tuberculin and 1 c.c. of No. 3 equals 10 mg., thus affording 

 an ample range of dosage. 



Method of Conducting the Test. 1. The patient's temperature and 

 pulse-rate should be taken every two hours for from four to seven days. 

 This is easily accomplished in a hospital; ambulatory patients can 

 usually be readily trained to take their own temperature. All observa- 

 tions should be recorded in writing, and preferably on a temperature 

 chart. The patient's temperature must be constantly below 99 F. 

 before beginning the test, and, if necessary, prolonged rest in bed should 

 be enforced to overcome any existing fever. The test may be given 

 in spite of a daily rise of not over 100 F., but tuberculin by subcutaneous 

 injection should be given only exceptionally to febrile patients. 



2. A very careful physical examination should be made, and the 

 results recorded just before and just after the test in order to detect 

 a focal reaction. This is extremely important, for it is our main justifi- 

 cation for injecting the tuberculin. 



3. Injections are made subcutaneously in the region of the back, 



