SCIENTIFIC SUMMARY. 
243 
will continue to be inrperishably associated with the distinguished names of 
Owen, Paget, and Wormald ; whilst the scarcely less important discovery of 
the lemon-shaped and calafied capsules must permit a similar bracketing of 
the names of Hilton, Peacock, and Hodgkin. 
The Poison of Nerium Oleander . — The researches which were conducted 
years ago by Orfila have been quite recently followed up by Professor Pelikan, 
of St. Petersburg, who, in some respects, confirms the conclusions of the 
French toxicologist. He believes that the yellow resinous matter is the 
important principle of the plant, and he is disposed to think that Nerium 
may be employed with advantage in cases where digitalis is now used. The 
experiments which he conducted upon frogs with this substance, as well as 
with the alcoholico-aqueous extract, have led him to the following conclusions : 
— 1. When first administered, it produces an acceleration of the heart’s 
action. 2. After a few minutes the beats of the heart become less frequent. 
3. The pulsations in diminishing become irregular, and then cease entirely. 
4. The ventricles are at this period empty and inactive, but the auricles still 
continue to contract. 5. Finally, the heart becomes completely paralysed. — 
Vide Comptes Rendus, January. 
The Nature of Colour-Blindness .- — In the Philosophical Magazine for 
February an important paper has been translated from Poggendorff's 
Annalen upon the nature of colour-blindness. The author of the essay re- 
ferred to, Herr Dr. E. Bose, of Berlin, describes an instrument which he has 
constructed for the detection of colour-blindness, and for estimating its ex- 
tent. Numerous researches have enabled him to conclude — 1. That with 
the colour-blind it is always light of the greatest dr of the least refrangibility 
that first becomes imperceptible. 2. That invariably, as the disease increases, 
the patient ceases to perceive only that light which had previously the 
greatest or smallest refrangibility among the rays visible to him. 3. That 
colour-blindness is always characterized by a shortening of the spectrum and 
never by an interruption. A complete and accurately defined spectrum thus 
forms by its extent a measure of the degree of colour-blindness. Herr Bose’s 
instrument consists of a mirror, condensing lens, and prism, by which a well- 
marked solar spectrum is produced, and therefore accurately determines the 
extent of the affection. 
Is Urea formed in the Kidneys ? — Herr Dr. Zalesky, in a recently published 
memoir, records some experiments, which seem to prove that urea is formed 
in the kidneys and not in the blood. He removed the kidneys from various 
animals, and examined the blood subsequently for urea, but without finding 
larger traces than usual. In animals, however, in which (without removing 
the kidneys) he placed a ligature upon the ureters, he found the proportion 
of urea in the blood largely increased. As the consequence of several experi- 
ments upon birds, reptiles, and mammals, he concludes that the kidneys do 
not simply allow uric acid to filter through them, but that they form it, and 
that urea is equally formed in great part in the kidneys. He does not believe 
that uraemic accidents are due to the accumulation in the blood of either urea 
or ammonia, but is more disposed to attribute them to defective elimination 
of other extractive principles and of water. — Tide The Lancet Record of the 
Progress of Medicine , March 3. 
The Cause of Cholera . — Madame de Castelnau has written to the French 
