SCIENTIFIC SUMMARY. 
267 
affection is due to a peculiar condition of the smaller blood-vessels of the 
chest. He says that there is, firstly , a sort of neuralgia of a rachidian 
nerve (brachial plexus, or intercostal nerve) ; secondly , an extension of this 
neuralgia to the corresponding portion of the great sympathetic ; and, 
thirdly , congestion of those organs whose vessels receive branches from 
this portion of the sympathetic system. — Archives Generales, for Novem- 
ber, 1863. 
Why Fibrin coagulates.— Schmidt’s researches show that the coagulable 
material of fibrin is contained chiefly in the cells. In fact, neither lymph 
nor chyle possesses this property till it has mingled with the cells in the 
lymphatic and mesenteric glands. The various forms of coagulated fibrin 
are not due to varieties of the fibrin itself, but rather to the nature of 
the cells which develop it. The operation of the active principle, whatever 
it may be, is not analogous to that of a ferment, for the principle itself is 
used up in the process. The presence of carbonic acid always retards the 
coagulation of fibrin, but this influence is very slightly exerted in the case 
of fresh blood. The difference of time required for the coagulation of 
venous and arterial blood may be attributed to the relative quantities of 
carbonic acid which they contain. Neither oxygen nor atmospheric air 
affects the coagulation of blood, at least directly ; but when oxygen is 
employed, it occasionally displaces the carbonic acid, and thus brings 
about coagulation more rapidly. — American Journal of the Medical 
Sciences , October, 1863. 
Proto-iodide of Iron and Manna. — M. Foucher recommends the employ- 
ment of pills containing these substances in combination ; he uses purified 
manna in tears, proto-iodide of iron, liquorice in powder, and mallow. 
When these are united, a mass is produced in which the protoiodide is 
completely preserved from alteration by the action of the manna, and 
which is easily softened by the mere heat of the hand. Hence this drug 
has two advantages, the preservation of the iron, and the extreme solu- 
bility of the mass in the digestive fluids. Moreover, the manna being 
laxative, prevents the constipation which might otherwise ensue from the 
administration of iron in other forms. — U Union Medicale. 
Organic nitrogenized Principles of the Body. — Very little dependence, 
in a physiological inquiry, can be placed upon the chemical analysis 
of the animal fluids. There has not been heretofore a sufficient 
amount of attention given to the study of the complex juices of the 
human body. We are glad, therefore, to perceive that this subject has 
been taken in hand by Professor Flint of New York, who has made an 
extensive series of analyses of human blood and other fluids. His 
conclusions are somewhat different from those of previous investigators, 
but his method of analysis is so simple that we conceive the liability to 
error was not so great as might otherwise have been. In a study such 
as that he has undertaken, the author remarks that we must recognize the 
following important facts: — 1st. Organised nitrogenous substances are 
the only elements of the body in which reside the properties of rege- 
neration and destruction, during life. 2nd. They are of indefinite 
chemical composition, and no physiological importance is to be attached to 
ultimate analyses. They are unstable ; in a state of continual change 
