INTRODUCTION. 9 



the behavior of the organs of different species. Other considerations made 

 such an investigation advisable. It is necessary for a toxin to get into contact 

 with the surface of cells before it can exert its injurious influence. One of the 

 means through which such contact between cells and poison can be accom- 

 plished is adsorption. 



Only a few of the results obtained in this study can here be referred to. 

 We found that organs like the liver and kidney adsorb at least as much venom 

 as the brain. In this respect heloderma venom seems to differ from certain 

 other poisons which have been examined, as, for instance, cobra venom. On 

 the whole, the brain closely resembles lecithin in its adsorbing power and it is 

 very likely that the adsorptive power of the brain is due to the lipoids and not 

 to the proteids of the brain, which latter seem, however, to adsorb some other 

 toxic substances, as, for instance, rabies virus. Emulsions of lecithin, how- 

 ever, adsorb more heloderma venom than emulsions of brain-matter. In both 

 cases, especially the small particles of the emulsified material, adsorb a great 

 part of the venom, and it needs therefore filtration through a Berkefeld filter 

 to determine accurately the quantity of venom adsorbed. We may conclude 

 that conditions comparable to those found in the case of tetanus toxin, in 

 which brain-substance has a special antitoxic power, do not exist in the case 

 of heloderma venom. Furthermore, the combination between lecithin and 

 venom, or brain and venom, is only a loose one, inasmuch as after an injection 

 of the residue obtained through centrifugation the animals die, perhaps after 

 a previous absorption and splitting of the lecithin, while after adsorption of 

 venom by charcoal the adsorbed venom is not at all or only very slowl} r given 

 off and has therefore become innocuous. 



Our comparative studies of adsorption by the organs of various species 

 point to the conclusion that the organs of Heloderma and of species nearly 

 related to it adsorb venom in a larger quantity than the organs of species not as 

 nearly related to Heloderma. Our experiments seem, therefore, to indicate 

 that certain organs of Heloderma might be concerned in the natural immunity 

 of this animal against its own venom. We can, however, not yet regard as 

 conclusive this part of our investigations. Considering the large number of 

 variable factors present in such experiments, additional investigation, espe- 

 cially a comparative study of the adsorption of heloderma and certain other 

 venoms by the organs of different species, seem to be desirable in order to 

 place this theory of natural immunity on a solid basis. On the other hand, we 

 must fully realize that adsorption experiments with organ-pulp in vitro are 

 only a very crude imitation of conditions that exist in the body after injection 

 of the venom, and that normally functionating organs might take up and fix 

 to themselves a very much larger quantity of venom than the organ-pulp. 



Furthermore, we have to consider the fact that according to our obser- 

 vations blood-serum markedly inhibits the adsorption of venom even by such 

 a strong adsorbent as charcoal. Assuming that circulating blood should act 

 in a similar manner, adsorption of the venom in the body would be greatly 

 interfered with. 



