58k 
with a zine salt had been attempted the literature, was consulted to 
see whether anything was known as to the occurrence of zinc in 
the human body. This investigation gave a positive result: Commu- 
nications have been made by Lecuartier and BerrAMYy *, and by 
Raourr and Breton*) from which it appears that the human liver 
may contain 10—76 megs of zine per kilogram. The quantity might 
be dependent on the age, the state of health and the nature of the 
food of the persons from which the liver is derived. 
As the method of investigation did not appear to us correct in 
every respect and as the number of livers tested was comparatively 
small and as, moreover, the results could not be taken as applying 
to Holland without further evidence, we have investigated a number 
of human livers of Dutch origin. We have also extended the inves- 
tigation to the occurrence of arsenic and copper. 
As regards the presence of arsenic, the results of BLOEMENDAL *) 
are opposed to those of the French investigators. Whereas the latter 
assume the presence of normally-occurring arsenic, according to 
BLOEMENDAL the liver does not normally contain the same. 
As to the distribution of copper in the animal and vegetable orga- 
nism, investigations have been carried out by LrHMANN *). There was 
reason tO suppose that the “charring process” employed by him had 
caused the results to be too low ; moreover, figures of Dutch origin, 
are also wanting here. 
For the destruction of the organic matter we, with a few modi- 
fications, made use of the process devised by KerBoscn in the phar- 
maceutical laboratory at Leiden. This method has the great advantage 
that the organic substance is completely destroyed, the only reagents 
used being sulphuric and nitrie acids which can be obtained absolutely 
free from arsenic. 
For this purpose, a current of hydrochloric acid is passed for-some 
hours through sulphuric acid heated at 250 —270°, whereas nitric 
acid can be obtained free from arsenic by distillation. In a check- 
experiment where 25 ec. of sulphuric acid and 250 ce. of nitric acid 
had been used and of which 5—6 ce. of liquid were left after distil- 
lation, no arsenical mirror could be obtained in a modified Marsh- 
apparatus. From previous investigations, it had already appeared *) 
that the limit of sensitiveness may be taken as 0.0001 mg. of arsenic. 
1) Compt. rend. de l’Ac. der Sc. 84, 1877, p. 687—690, 
2) Idem. 85, 1877, p. 40—42. 
3) Arsenicum in het dierlijk organisme. Dissertatie Leiden 1908. 
4) Arch. f. Hygiene 24, 1895, 
5) BLOEMENDAL I. c. 
