78 



SCIENCE 



[N. S. Vol. XLIV. No. 1125 



fact, which appears to be generally true, 

 and to include all the forms of infaDtile 

 paralysis, namely the paralytic, meningeal, 

 or abortive, which all confer immunity. 



Basis of the Immunity 

 The blood of normal persons and mon- 

 keys is not capable of destroying or neu- 

 tralizing the effect of the virus of infantile 

 paralysis. The blood of persons or mon- 

 keys who have recovered from the disease 

 is capable of destroying or neutralizing the 

 effect of the virus. The insusceptibility or 

 immunity to subsequent infection, whether 

 occurring in human beings after exposure 

 <or monkeys after inoculation, rests on the 

 presence of the destroying substances, the 

 so-called immunity bodies, which arise in 

 vthe internal organs and are yielded to the 

 "blood. So long as these immunity bodies 

 persist in the body, protection is afforded ; 

 and their presence has been detected 

 twenty years or even longer after recovery 

 from infantile paralysis. Experiments 

 have shown that the immunity bodies ap- 

 pear in the. blood in the course of even the 

 mildest attack of the disease, which fact 

 explains why protection is afforded irre- 

 spective of the severity of the case. 



Active Immunization 

 Protection has been afforded monkeys 

 against inoculation with effective quanti- 

 ties of the virus of infantile paralysis by 

 previously subjecting them to inoculation 

 with sub-effective quantities or doses of the 

 virus. By this means and without any evi- 

 dent illness or effect of the protective in- 

 oculation, complete immunity has been 

 achieved. But the method is not perfect 

 since in certain instances not only was im- 

 munity not obtained, but unexpected 

 paralysis intervened. In the instances in 

 which protection was accomplished, the im- 

 munity bodies appeared in the blood. 



Passive Protection 

 By transferring the blood of immune 

 monkeys to normal or untreated ones, they 

 can be rendered insusceptible or immune, 

 and the immunity will endure for a rela- 

 tively short period during which the pas- 

 sively transferred immunity bodies persist. 

 The accomplishment of passive immuniza- 

 tion is somewhat uncertain, and its brief 

 duration renders it useless for purposes of 

 protective immunization. 



Serum Treatment 

 On the other hand, a measure of success 

 has been achieved in the experimental 

 serum treatment of inoculated monkeys. 

 For this purpose blood serum derived 

 either from recovered and protected mon- 

 keys or human beings has been employed. 

 The serum is injected into the membranes 

 about the spinal cord, and the virus is in- 

 oculated into the brain. The injection of 

 serum must be repeated several times in 

 order to be effective. Use of this method 

 has been made in a few instances in France 

 where the blood serum derived from per- 

 sons who had recovered from infantile 

 paralysis has been injected into the spinal 

 membranes of persons who have just be- 

 come paralyzed. The results are said to 

 be promising. Unfortunately, the quantity 

 of the human immune serum is very lim- 

 ited, and no other animals than monkeys 

 seem capable of yielding an immune serum 

 and the monkey is not a practicable animal 

 from which to obtain supplies. 



Drug Treatment 

 The virus of infantile paralysis attacks 

 and attaches itself to the central nervous 

 organs. Hence it is reached not only with 

 difficulty because nature has carefully pro- 

 tected those sensitive organs from injurious 

 materials which may gain access to the 

 blood, but it must be counteracted by sub- 

 stances and in a manner that will not them- 



