Abstract
It has been shown that Flexner's M.V. poliomyelitis strain carried in monkeys can be acclimated to rats 1 and subsequently retransferred from rats to monkeys, in which latter typical disease was produced. 2 The first 2 experiments of this report were performed in order to determine whether the virus could be retransferred from the collateral monkey generation back to rats.
Experiment I. Monkey No. 2379 was 4 generations removed from the original rat transfer. Generation I monkey had received intracerebrally 1 cc of a 10% lineal generation VI cotton rat cord virus. Generations II, III, and IV monkeys were given 1 cc of a 10% cord virus obtained from the generations I, II, and III monkeys, respectively.
Generation I Rat Re transfer. On 11/11/40, 5 cotton rats were injected with 0.06 cc IN, 0.06 cc IC, 0.5 cc SQ, and 1 cc IP of a 10% cord virus suspension of generation IV, Monkey No. 2379. (The doses mentioned here are the same in all the subsequent experiments of this type.)
Two animals died—1 on 11/27, the sixth day, and 1 on 11/28, the seventh day; both were weak, but neither had paralysis.
Generation II Rat Retransfer. On 11/29/40, the cords of the 2 animals dying in rat generation I were injected into 3 cotton rats. One rat died on 12/1 with no evidence of paralysis; the other 2 animals had paralyses and died on 12/5.
Generation III Rat Retransfer. On 12/6/40, a cord suspension made from the 2 animals that died on 12/5 in rat generation II was injected into 3 animals, all of which developed paralysis.
Thus, one can transfer Flexner's M.V. strain from the monkey to the cotton rat, back to the monkey and then to the rat again.
Get full access to this article
View all access options for this article.