220 PASSIVE IMMUNIZATION 



preparation, and specimens are purchased from time to time in the 

 open market for examination at the hygienic laboratories of the 

 Public Health and Marine Hospital Service. 



In the United States diphtheria antitoxin is now marketed in 

 500, 1000, 2000, 3000, 4000, 5000, and 10,000 unit doses. 



The Injection. The injections are usually given into the loose sub- 

 cutaneous tissue between the shoulder-blades, into the abdominal 

 walls, or into the district overlying the triceps. The skin should be 

 scrubbed with soap and water and then with alcohol, or as is now 

 also advised, merely painted with tincture of iodine about the point 

 of injection. If a separate syringe be used this should, of course, be 

 sterilized by boiling, but in the United States the manufacturers 

 now send the antitoxin out in separate syringes which are already 

 sterile and ready for immediate use. 



Of late it has been suggested that a more powerful effect may be 

 secured if the antitoxin is administered intramuscularly, or, still bet- 

 ter, intravenously. To this there can be no objection if the amount of 

 preservative that is thus injected at one time remains within the limits 

 of the permissible dose. In Heubner's clinic 18 c.c. of serum con- 

 taining 0.5 per cent, carbolic acid have thus been injected at one time 

 and the dose repeated within twenty-four hours. With us, in the 

 United States, where no preservative is frequently used, even this 

 objection does not exist. The advantage of the intravenous over 

 the subcutaneous method of administration has been clearly shown 

 by Berghans, who found in the animal experiment, that whereas 40 

 units of antitoxin were necessary to prevent the death of a guinea- 

 pig when given subcutaneously, 0.08 was sufficient when injected 

 directly into the circulation, the amount of toxin having been the 

 same in both instances. The importance of resorting to this method 

 of administration is further emphasized by the observation made 

 in the Danish Serological Institute that following the subcutaneous 

 use of the antitoxin this does not reach its maximum in the circu- 

 lation until the second or third day. Eckert thus very properly 

 insists that the intravenous method is the method par excellence 

 to be employed, and that with its general adoption the death rate 

 from diphtheria will be lowered still farther (see below). 



Dosage and Uses. In the treatment of diphtheria by antitoxin 

 it is important to bear in mind that the quantity of toxin that is 

 produced and likely to be absorbed is, cceteris paribus, the greater 



