SCIENTIFIC SUMMARY. 
333 
cessful. In one or two cases where the opacity was so decided as to produce 
nearly total blindness, a considerable amount of vision was restored to the 
patient. — "Vide Comptes Pendus , May 27. 
Isolation of Pseudomorphine. — Pseudomorphine was discovered about 
thirty years ago by Pelletier, but from the exceedingly small quantity ob- 
tained by him, he was unable to give an exact method for its preparation. 
This, however, has now been done by Herr Hesse, who has published a 
paper on the subject in the Annalen der Chemie. Hesse finds that it 
accompanies morphine in Gregory’s method, and may be separated from 
that body by adding excess of ammonia to the alcoholic solution of both 
alkaloids ; the morphine is precipitated, the other remains in solution. 
Pseudomorphine is tasteless, insoluble in water, alcohol, ether, chloroform, 
carbonic bisulphide, and dilute sulphuric acid, easily soluble in potash, soda, 
or lime solutions, and in alcoholic solution of ammonia, sparingly so in 
aqueous solution of ammonia ; it does not neutralise the acid reaction of 
even the smallest quantity of chlorhydric acid ; it dissolves in concentrated 
sulphuric acid with an olive green, in concentrated nitric acid with an in- 
tense orange red, in ferric chloride with a blue colour. At 120° it loses 2 
eq. water of crystallisation ; at higher temperatures it turns yellow and 
decomposes without melting. 
The Physiological Action of Digitalis has recently been very fully investigated 
by M. Legroux, who has thus formulated the conclusions at which he has 
arrived : — 1. If given in a poisonous dose, digitalis acts directly on the heart ; 
in a therapeutic dose, it excites primarily the contractility of the capillary 
vessels, and only secondarily influences the circulatory centre by re-estab- 
lishing the equilibrium of the circulation. If this theory be adopted, 
digitalis is a sedative of the circulation, inasmuch as it calms its irregular 
action ; but, if it really possess this power, it is by an exciting and tonic 
action. 2. The influence of digitalis on the temperature, the secretions, 
nutrition, the uterine contraction, haemorrhages, &c., can only be explained 
by its exciting action on the ultimate filaments of the great sympathetic. 
This theory explains and justifies the favourable results obtained by the 
employment of digitalis in fevers, cerebral affections, haemorrhages, and 
dysmenorrhoea, as well as in congestions, dropsies, and the circulatory affec- 
tions, accompanying cardiac lesions. — Vide Gazette Medicate de Paris, April 
27. 
The Study of Human Histology is greatly facilitated, according to the recent 
statements of Herren Kolliker, and Cohnheim, by employing chloride of gold 
to stain the tissues. This substance appears to have a very peculiar effect on 
the histological elements. Tissues which have been soaked for some time 
in a weak solution of it, and afterwards exposed to light, are found to ex- 
hibit certain parts, ex gr. nerve-fibres, connective-tissue corpuscles and cells 
in general, stained of a bluish, violet, or reddish colour, while other parts, 
ex gr. intercellular substance, &c., are untouched. The fresh tissue should 
be covered with a little of a solution of from 1 to *2 per cent, of chloride of 
gold in distilled water (the strength must be made to vary according to the 
thickness of the object and other circumstances), and allowed to stand until 
it assumes a straw-yellow colour. It should then be washed and placed in 
very dilute acetic acid (1 to *2 per cent.). The colour will in the course of 
