WILLIAM H. PARK 035 



ity is not that the encephaUtis infection caused the development of antibodies against 

 the virus of poliomyelitis but rather that these antibodies were already there. So far 

 as can be determined from a study of the antibodies in the convalescent sera from 

 cases of pneumonia and scarlet fever, they are about as stable as those developed in 

 animals after immunizing injections. 



VALUE OF convalescents' SERUM IN PROTECTION AGAINST VARICELLA 



In 1923, Blackfan Peterson and Conroy^ reported that a temporary passive 

 immunity to varicella could be produced in the majority of cases by the intra- 

 muscular injection of convalescents' serum. Of forty-two exposed children who were 

 given 5 cc. of serum within five days after exposure to the disease only seven con- 

 tracted it, and then in a mild form. Later, Weech,^ by injecting from 3 to 4.5 cc. of 

 convalescents' serum within from one to six days after exposure, was able to protect 

 nine out of ten infants, the only infant who contracted the disease having an excep- 

 tionally mild attack with an unusually long incubation period. Schmidt,'' however, 

 was unable to prevent varicella by the injection of 7-8 cc. of convalescents' serum 

 during the incubation period. These reports are the only ones I have found in the 

 literature available to me, although it seems quite certain that the procedure is more 

 widely employed than is indicated. 



Mitchell and Ravenel'' gave sixty-eight young and older children the serum from 

 a convalescent varicella patient. Only three of these developed varicella, the others 

 showing no symptoms for at least thirty days after exposure. Of these three patients, 

 two were observed by them during the period of the disease, but the other one was 

 diagnosed by his family physician after he had left the hospital. A fourth patient 

 who had escaped contracting the disease on the first exposure was re-exposed twenty- 

 two days after his injection. Sixteen days following the second exposure, this patient 

 developed a rash which somewhat resembled varicella. There were no symptoms 

 except the rash, which was of a type the child had had on two other occasions during 

 a period of five months' observation. These facts make it very doubtful whether the 

 condition should be regarded as varicella. The incubation period in the three patients 

 developing the disease was rather long, being twenty-one, twenty-two, and twenty- 

 three days, respectively — thus corresponding to Weech's case, in which the incuba- 

 tion period was twenty-three days. However, in contrast to the observations of 

 Blackfan, Peterson, and Conroy and of Weech, who found that the disease after in- 

 jection assumed a mild form, two of their patients presented a rather profuse rash 

 and moderately severe general symptoms. 



In a group of twenty-two children, one failed to receive convalescents' serum, 

 and he alone of this group developed varicella on the nineteenth day. Twelve of this 

 same group were re-exposed on the twenty-first day after injection. Although none 

 of these children received a second injection, only one developed the disease, his rash 

 appearing nineteen days after this second exposure. This patient at the time of the 



' Blackfan, K. D., Peterson, M. F., and Conroy, F. C: Ohio Slate M. J., 19, 97. 1923. 



= Weech, A. A.: J.A.M.A., 82, 1245. 1924. 3 Schmidt, W.: Med. Klin., 20, 642. 1924. 



"Mitchell, A. G., and Ravenel, S. F.: Arch. Fed., 42, 709. 1925. 



