504 
the adsorbing substances do not occur only in the blood of rabbits, 
but also in other parts of its body. We detected that brain-, and 
liver-substance of the rabbit had a rather strong adsorbent power. 
This adsorption also could be undone by extraction with alcohol. 
An adsorption of atropin by liver substance had also been found by 
v. OETTINGEN '), who established that the liver of frogs adsorps atropin 
very strongly. The serum of this animal has no adsorbent power, 
although the animal is very resistant to atropin. Crorrra had also 
shown already that the livers of the rabbit, the cat and the dog, in 
vitro, could destroy atropin. We found that the brainsubstance of 
the rabbit had a stronger adsorbent power than that of the cat. 
When asking what does the adsorbent power of rabbit’s serum 
signify for these animals, we may safely answer that it will be an 
important factor for the great resistant power of rabbits for atropin. 
It should be borne in mind, however, that in this way we shall 
never be able to solve the entire problem of resistance, for it may 
be that when atropin is administered to rabbits per os part of it is 
destroyed in the gut. Metzner *) found in his experiments that Bazel-, 
and Bern-rabbits have apparently little or none of these adsorptive 
substances in their serum, although they are highly imsensitive to 
atropin given per os. Moreover this resistance can still be increased 
through immunization. Lastly, on the basis of the experiments by 
FLEISCHMANN, Metzner, Herrrer and others it cannot be doubted that 
a chemical destruction of the atropin also comes into play. When, 
however, a poison is injected subcutaneously or intravenously, a 
chemical destruction will be too late to prevent an acute intoxication, 
as has been pointed out by us more than once. A physical adsorpt- 
ion, however, operates quickly, and may therefore be of use in this 
respect. 
It remains still to observe that, although in this and in previous 
papers “physical adsorption” is frequently contrasted with “chemical 
destruction”, we cannot say for sure that this adsorption is indeed 
a physical process. Doubtless in the processes alkaloids or other 
poisons are influenced by tissue-substances, so that they are much 
less active, but can be easily restored to full action with very simple 
means, such as treatment with alcohol, or boiling in water. When 
1) V. OrrtinGEN. Ueber d. Verhalten d. Atropine im Organismus des Frosches. 
Arch. f. exp. Path. 83. p. 381 1918. 
2) Merzner. Mitteilungen über Wirkung und Verhalten des Atropin im Organ. 
Arch. f. exp. Path. Bd, 68. pg. 110. 1912. 
MerzNeER und HeEpinGER Ueber die Beziehungen der Schilddrüse zur atropine- 
zerstörenden Kraft des Blutes. Ibid. Bd. 69. pg. 272. 1918. 
