498 
found that atropin generates a nucleoproteid in the blood which 
obviates clotting, while they also observed that the adsorbent 
power of serum in vitro runs parallel with the animal’s resistance 
to intravenous injections in vivo. This would be difficult of explana- 
tion if the adsorbing substance should originate only with coagulation. 
Another possibility to be considered is, that the presence of peptone 
or citrate might prevent the adsorption of atropin by rabbit’s serum, 
or — if it had already been accomplished — might loosen the 
atropin binding and this assumption is not without foundation, since 
GenGou') has stated that certain colloidal solutions, several sera; 
albumoses and also citrates can inhibit certain adsorptions. 
Citrates e.g. can counteract adsorption of colouring matter by 
animal charcoal, nay, they can substitute certain adsorptions by their 
own adsorption. We have examined this question in the following 
way (see Fig. 3). 
In fig. 3a 0,02 mgr. of pilocarpin is added to the gut and after 
three minutes 0,0002 mgr. of atropin, which undoes the pilocarpin- 
action almost entirely in three minutes. 
In fig. 36 the same dose of pilocarpin is added, but a different 
quantum of an atropin solution which was obtained in the following way : 
To rabbit’s serum some atropin was added and also a few drops 
of citras natricus. Of this liquid the quantity was taken that could 
be assumed to contain 0,001 mgr. of atropin, the effect of which 
is slightly weaker than 0,0002 mgr. in fig. 2a, so that at the very 
least the effect of the atropin is reduced to '/,. In fig. 3c 0,008 
mgr. of atropin is given, but this atropin is derived from a solution 
obtained by adding 1 mgr. of atropin to 1 c.c. of rabbit's serum, 
without the addition of citrate. A very strong adsorption of the 
atropin is now noticeable, for 0,008 mgr. of atropin in experiment 
3c is less active than 0,001 mer. in fig. 35, from which it is evident 
that citras natricus largely inhibits the adsorption of rabbit’s serum. 
To the solution of atropin in rabbit's serum, which is used in fig. 3c 
subsequeutly citras natricus is added by which the adsorption is 
distinctly diminished, for 0,008 mgr. of atropin is active again in 
tig. 3d, whereas the same dose in fig. 3c was inactive. After the 
addition of pilocarpin in fig. 3e again 0,0002 mgr. of atropin is 
given to show that the sensitivity of the gut to this poison was 
unchanged. 
Fig. 4 tends to show that the action of peptone is in this respect 
1) Genaovu. Contribution a |’étude de]’adhesion moleculaire et de son intervention 
dans diverses phénoménes biologiques. Arch. int. de physiol. VII 1908. 
