Cellular Immunity, 



85 



In regard to acquired cellular immunity of other tissues, the results are not 

 very convincing. Gley (16) found that the toxicity of eel serum for the 

 rabbit is ten times greater when injected into the cerebro-spinal fluid than 

 when injected intravenously. When a rabbit was immunised the minimum 

 lethal dose by cerebro-spinal injection was practically unaltered, and he 

 therefore concluded that the central nervous system does not acquire 

 immunity to eel serum, or at least only a very feeble immunity. 



Gley (17) came to the same conclusion with torpedo serum, namely, that 

 there was no cellular immunity as far as the central nervous system was 

 concerned. 



These experiments were of the same type as those of Eoux and Borrel (18) 

 who found that rabbits immunised against tetanus are as easily as before 

 made tetanic by injections into the brain itself. Such experiments are ill 

 adapted to prove the point at issue, because, though relatively small amounts 

 of toxin are injected into the brain or cerebro-spinal fluid, they are injected 

 in high concentration compared to that which arrives at the central nervous 

 system when the toxin is diffused through the blood. 



Gley and Pachon (19) prosecuted further researches on this problem to 

 determine whether there was any cellular immunity developed in the heart 

 when an animal is immunised to toxic sera. Their experiments were incon- 

 clusive. Indeed the toxins employed were not suitable for deciding the point. 

 It required 1 to 4 per cent, of eel serum and 10 to 20 per cent, of torpedo 

 serum to produce even doubtful effects on the heart. Cushny and Gunn (20) 

 have shown more definite effects with lower concentrations of horse serum, 

 so that it is doubtful if the serum of the eel or torpedo has any specific toxic 

 action on the heart. 



So far as acquired immunity is concerned these observations leave the 

 question still undecided. According to Camus and Gley and Kossel, in an 

 animal immunised to eel serum the red cells, freed from antitoxi^, may show 

 an increased resistance to the hsemolytic action of the serum, but a similar 

 effect was not found by Cushny or Jacoby with ricin or by Calmette with 

 cobra venom, and no convincing proof was forthcoming of an increased 

 cellular immunity of the heart or central nervous system occurring in the 

 process of immunity. 



It was my intention to proceed, after completing the experiments described 

 with strophanthus, to determine by similar methods whether when an animal 

 is immunised to a particular toxin, the tissues of the animal freed from the 

 serum acquire an increased insusceptibility to the action of the toxin. For 

 this purpose it was necessary to employ a toxin of the bacterial type which 

 produces genuine immunity with antibodies in the serum. Of such toxins 



