SCIENTIFIC SUMMARY. 279 
reaching the ship.” This is far from being the first time that science has 
shown the evidence of the senses to be a fallible guide. 
Mr. Robert Aytoun has suggested a new Safety- Break for railway trains 
to the Scottish Society of Arts. He proposes to fix to the sleepers, between 
the rails, a longitudinal stringer of timber, five inches square, to be com- 
pressed by a pair of compound bladed springs, of any requisite amount of 
power affixed beneath the break-van, and under the command of the 
guard. The plan has some merits, but it is probable that the continuous 
breaks, already to some extent introduced, afford a readier mode of pro- 
portioning the break-power to the heavy trains now run upon railways, 
and they have the advantage of preventing shock, by distributing the re- 
tarding power to all the carriages. 
MEDICINE, SURGERY, AND THERAPEUTICS. 
MEDICINE. 
Graham's Method of Dialysis in Cases of Poisoning. — This method 
of analysis, invented by the Master of the Mint, is becoming valuable 
as an aid in the investigation of the contents of the stomach, &c., in cases 
of poisoning. The chief difficulty, hitherto, has been, that the contents 
of the stomach are too viscid to pass through any filtering material, and, 
consequently, the separation of any poison is much impeded. Dialysis 
here comes in very usefully, and may be thus practised A round vessel 
of glass, open at the top and bottom, is taken : across the opening below 
is stretched, and firmly tied, a piece of De la Rue’s parchment- paper ; the 
vessel is then placed in a dish with sufficient distilled water to reach and 
cover the parchment ; the substances to be dialysed are then introduced 
into the glass vessel and allowed to stand for twenty-four hours. The 
membrane will allow substances of crystalline form to pass, but retains 
those without definite shape, as gum, gelatine, albumen, &c. By this 
means, the crystalline alkaloids, morphia, strychnia, &c. ; numerous metallic 
salts, as corrosive sublimate, arsenic, and so on, will be found, if originally 
present with the matters submitted to dialysis, in thin and clear solution, 
in the containing dish; when, of course, the tests for the identification 
of the suspected poison can be easily and satisfactorily applied. 
Researches on Diabetes. — Dr. Pavy, professor of physiology in Guy’s 
Hospital, has lately published a work on this obscure disease. According 
to Bernard, a French physiologist, the starchy matters that we take in our 
food, after being acted on by the saliva, become grape sugar, which is 
soluble, and is absorbed by the stomach, passing through the liver un- 
changed, to the lungs, where it meets with the oxygen of the air ; a slow 
combustion then taking place, which aids' in the production of animal 
heat. But by a well conducted series of experiments by Dr. Pavy, it is 
shown that grape-sugar, if present in the blood, invariably produces diabetes, 
not being burnt off, but passing out of the system by. the kidneys. The 
following are his views : — Just as, in the vegetable economy, starch 
becomes sugar before it is carried over the system of the plant, and 
