1398 
For it is really surprising that, with men in pathological and with 
animals even in physiological condition, a substance is taken up by 
the blood from the intestinal canal to the amount of 20°/,, which 
is poisonous for the central nervous system, and which, by combining 
with the respiratory pigment: renders part of it worthless. 
The investigations described above do not yield conclusive evidence 
for the Shb-aemia in patients with slowed progress of the contents 
of the colon. We have been impressed with the idea that in patients 
in whom there was an impediment in the advance of the intestinal 
content, cyanosis was evolved in a comparatively short time — 
almost rather abruptly. It still, looks as if another hitherto 
unknown factor besides the resorption of H,S from the gut, 
is instrumental to the origin of Shb-aemia. Whether this factor be 
the presence of reducing substances, as Mackrnziz-Wattis concludes 
from his interesting inquiry, will have to be made out by further 
experiments. We were not so fortunate as to demonstrate such 
reducing substances in the serum. Likewise the question whether 
SHb-aemia occurs perhaps more frequently than spectrosopic exami- 
nation could make out up to the present day, must be left for 
subsequent investigation. In our judgment this spectroscopic result 
cannot be achieved before about 10°/, of OHb have been converted 
to SHb. 
