Susceptibility of Eels and Dogfish to Diphtheria Toxin;Toxicity of Eel Serum and Dogfish and Skate Plasma

Abstract

The action of the bacterial toxins depends upon tissue susceptibility; but the mechanism by which they act and the conditions in the tissues determining their action are quite obscure, despite many years of experimental investigation with susceptible laboratory animals. In contrast, the susceptibility of the higher marine animals has been little studied. 1

The Marine Biological Laboratory at Woods Hole provided facilities for a few experiments on eels, Anguilla chryspa, and dogfish, Mustelus canis, to determine their susceptibility to diphtheria toxin under different conditions. Inoculations were all intramuscular. An eel, weighing 106.5 gm., received 125 M.L.D. of diphtheria toxin. Nine days after inoculation, the eel became inactive but did not die until the twenty-fourth day. Two control eels, inoculated, respectively, with toxin broth and with heated diphtheria toxin, remained normal. Two other seawater eels were gradually habituated to fresh water. They weighed 40 and 50 gm. and were inoculated with 62 M.L.D. of the diphtheria toxin. Two days after inoculation, the eels were unusually active. This excessive activity subsided slowly and the animals became quiescent, breathing with difficulty. They both died on the thirteenth day, or in about half the time required by those in seawater.

A young seawater dogfish, weighing 1067 gm., was inoculated with 1375 M.L.D. of diphtheria toxin without effect. Four dogfish were gradually habituated to an environment of 50% fresh water. Two, weighing 681 and 818 gm. respectively, received series of doses ranging from 25 to 1250 M.L.D. of diphtheria toxin. The action of the toxin was manifest in about 7 days—the smaller animal died in 26 days, the larger in 20 days. The 2 control dogfish remained normal and increased in size.