280 IMMUNOLOGY 



Weissbecker in 1897. The amount used for protecting contacts 

 has varied. Neff (1922) obtained satisfactory results with doses 

 varying from 15 to 30 c.c, but as a rule smaller doses have been 

 employed. Rhoads and Gasul state that the therapeutic dose 

 has varied from 10 to 240 c.c. and that there is at present a 

 ''trend toward smaller doses." They determined the potency 

 of twelve lots of pooled convalescent serum and found that it 

 varied from 250 to 1,000 neutralizing units per cubic centimeter 

 (one unit neutralized one skin test dose of toxin). The govern- 

 ment requires that commercial scarlet fever antitoxin have a 

 potency of 15,000 neutralizing units per cubic centimeter. This 

 would indicate that so far as antitoxic potency is concerned the 

 commercial antitoxin is definitely superior to convalescent serum. 



Park's Recommendations. — Park (1928) calls attention to the 

 value of antistreptococcus antitoxin, convalescent serum and even 

 normal serum or citrated normal blood in the treatment of severe 

 cases of scarlet fever, especially where sepsis is present. For the 

 purpose of treatment with serum or whole blood, he divides scar- 

 let fever cases into two groups. 



Early Malignant Cases. — In group one he places the earh^ 

 malignant cases seen between the first and the fourth day. In these 

 cases there are observed delirium, restlessness, deep red petechial 

 rash, marked adenitis and severe angina. While specific anti- 

 toxin is of great value and may be used, it is also possible to 

 inject intramuscularly convalescent serum or blood taken during 

 the second or third week of convalescence and obtain excellent 

 therapeutic results. The blood is obtained from the median 

 basilic vein of the arm, citrated and injected into various mus- 

 cles of the patient. Park suggests the triceps, vastus externus 

 (thigh), soleus (calf of leg), and gluteal muscles. In young 

 children he would administer 15 c.c. and in older children 30 c.c, 

 in each of these places. The same sites may be used for subse- 

 quent injections since the blood is rapidly absorbed. 



About six hours after the administration of the blood, the 

 temperature begins to drop and reaches normal in twenty-four 

 to thirty hours. There occurs also as a rule an early fading of 

 the rash and a disappearance of other evidence of the toxemia. 



Ijate Septic Cases. — In the second group he places the later 

 septic cases seen between the fifth and the eighth day of the disease. 



