94 
[January ? 
Physiology and its Chemistry 
of each of the matters from which “ nuclein ” has been 
derived ; and confining our attention to the human brain, 
this may serve to illustrate all cases. Jaksch diredts the 
brain to be skinned, washed with water, passed through a 
sausage-machine, then to be extracted successively with 
cold alcohol and cold ether; after which it is to be pressed, 
rubbed, and extracted with absolute alcohol, and filtered. 
The residue is then to be digested with extracft of pig’s 
stomach and dilute hydrochloric acid during forty-eight 
hours, at 40° C. ; the residue is extradted with soda, and the 
amber-coloured solution yields “ nuclein ” on precipitation 
with hydrochloric acid, accompanied, as the author states, 
by the evolution of a most peculiar odour, which he suggests 
may be sulphuretted hydrogen ! Without claiming absolute 
purity for his preparation, he entertains no doubt “ that it is 
a nuclein kind of body in a Miescher ” (why not “ Pick- 
wickian ?”) “ sense.” 
Now, in considering a little more closely the properties of 
this substance, we find that before it will give the phosphate 
test with molybdic acid it has to be boiled with stronger 
acid. Our acquaintance with brain-matter guarantees us 
personally in saying that Jacksch’s proceedings would leave 
behind in the brain residue very considerable traces of 
myeline, and perhaps lecithin. Without pausing to explain 
why this is, we know that any phosphorus left behind would, 
on boiling with an acid solution, be yielded as glycero- 
phosphoric acid, and this with molybdic acid would give the 
reaction which so astonished Jaksch. We tarry only to 
characterise one other statement made by Jaksch, which 
maybe given in his own words : — “ It will, however, be easy 
to estimate quantitatively, as nearly as possible, the amount 
of nuclein in the brain, from the standpoint that in the brain 
no other phosphorised principles occur except lecithin and 
nuclein. One requires only to remove the lecithin from the 
brain, and to subject the residue to a calcium and phosphorus 
determination.” 
The fadt that the above was printed after the publication 
of Thudichum’s researches in brain chemistry* intensifies 
rather than palliates the ignorance it displays. We are 
compelled to refer once more to F. Meischer. In a later 
paper! this author states the formula of nuclein, from the 
analysis above quoted, to be C 2g H 4g N g P 3 0 2 2> and opines that 
* Med. Off. Rep. Privy Conncil and Local Government Board. New Series, 
No. III., p. 113. 
t Jahresbericht der Thier-Chemie (Maly) fiir 1874. Wiesbaden, 1875. 
