SCIENTIFIC SUMMARY. 
101 
defibrinated, was transmitted by means of mercurial pressure through the 
liver. Coincidently three canulse were introduced — one into the inferior 
vena cava, the second into the hepatic artery, and the third into the vena 
porta. The results of careful analysis showed that the blood which had 
passed through the liver contained a much larger proportion of urea than 
ordinary arterial blood. In one experiment 100 c. c. of the arterial blood 
when defibrinated contained 0 08 grammes of urea; but, after having been 
passed four times through the liver, the same quantity contained 0T76 
grammes. 
Destruction of Tumours by Injecting Chromic Acid. — Chromic acid has 
not been much employed here. In America, however, it has been used 
with advantage. In a late number of the “ Philadelphia Medical and Sur- 
gical Reporter,” Dr. Daniel Leasure, of Alleghany City, gives an account of 
a tumour of the neck (probably malignant) treated by the injection of 
chromic acid. It was situated on the right side, one inch and a half by 
two inches and a half longest diameter. On September 17, 18G9, it was 
injected by a hypodermic syringe with sixty drops of a solution of chromic 
acid, 100 grains to the ounce of water. On the day following, and on the 
third day, it was injected as before. No serious irritation. On Sept. 80 
repeated, the tumour softening. Oct. 17, the same. Nov. 15, the tumour 
had collapsed. An opening formed, and matter was discharged. Poulticed, 
and on Nov. 29, reported well. There was a small cicatrix, three lines in 
diameter, at the seat of the late opening, which so closely resembled in 
colour the surrounding skin as to be scarcely noticed. In June 1870 no 
sign of return. Two other similar cases treated with like success. The use 
of chromic acid in this manner is new. 
Poisonous Snuff. — We understand that Dr. Garrod lately lectured at 
King’s College on a case of lead-poisoning, in which the mineral was taken 
in snuff. It was rappee that the patient habitually took, and the damp 
snuff, packed in the usual lead cases, converted some into carbonate. The 
symptoms were serious, and with difficulty traced to their real source. 
Then several packages were purchased, and found to be contaminated with 
the poison. 
The Late Dr. Robert Knox. — We learn, from the u Medical Press ”• of 
Dec. 7, that Dr. Lonsdale has j ust brought out a life of Robert Knox, the 
once famous lecturer on anatomy, of Edinburgh. From this interesting 
biography it seems that the terrible affair of Burke and Hare in 1828 
proved the ruin of this distinguished teacher’s fame in Edinburgh, and 
that he died comparatively unknown and poor in Hackney parish, London. 
One of his last works, which has been much admired by some, is the u Races 
of Man.” 
The Conducting Power of the Nerves. — In the u Lancet,” Dec. 17, are re- 
corded some fresh investigations upon this point, by MM. Place and Helm- 
holtz. M. Place adopted the same method as that formerly suggested by 
Helmholtz. The cylinder employed for registration was that constructed 
by Heynsius for the Leyden physiological laboratory, and was carefully 
planted in such a manner as to avoid accidental vibration. The measure- 
ment of the time was estimated by a coincident tracing from a vibrating 
tuning-fork. The median nerve was irritated first where it runs in the 
