4 
PROCEEDINGS OF THE ACADEMY OP 
[Biolog. 
acting as solvents. Others, as liq. soda and liq. potassae dissolve them readily, 
and at the same time so affect their coloring matter as to give rise to a succes- 
sion of tints, usually resulting in some shade of green. 
Hot water acts readily as a solvent ; cold water, in excess, has a like effect 
after some hours. 
Hydrochloric and sulphuric acids dissolve the crystals easily. Nitrate of 
silver merely blackens them. Alcohol contracts, swells, and at last granulates 
them. 
In good glycerine, the crystals lose color, but remain intact as to form for 
many days, so that it may be possible to use this agent as a means of preparing 
them for the microscopic cabinet. 
Otho Franke, who has made numerous researches upon blood crystals, first 
observed the occurrence of crystals within the envelope of the human blood 
corpuscle. I have frequently seen examples of this phenomenon in the large 
corpuscles of the sturgeon. The crystals are as usual hexagonal plates, capable 
of being re-dissolved, so as to give back to view the original outline of the 
corpuscle. In some instances the nucleus is seen through the crystal, or along 
side of it, but I am not sure that it is caught or included within the crystal 
itself, pi. 6. 
The last fact to which I desire to call attention, is, I think, quite novel, and 
certainly very interesting, as illustrative of some points in pathology. When a 
glass slide containing a group of the crystals is kept for some weeks, the crys- 
tals slowly dry, crack in many directions, and by degrees alter in color so as to 
exhibit very beautiful tints, such as yellow, orange, purple, and varied shades 
of green. 
The same phenomenon may also be seen in the nebulous masses of pigment, 
in dried blood which has not crystallized. It is to be presumed that these 
changes of color are due to the slow oxidising influence of the atmosphere. 
They recal very strikingly the alterations of tint undergone by the leaf in 
Autumn, and are best comprehended by a glance at the illustrations which ac- 
company this paper. PI. 2, 3, 4, 5. 
March, 1858. 
Summary of the Transactions of the Philadelphia Biological Society. 
Reported by Henry Hartshoene, M. D., Recording Secretary. 
Jan. 18th, 1858. Dr. Wm. A. Hammond read a paper " On the Injection of 
Urea and other substances into the hlood f^"^ giving an account of several series of 
experiments instituted in order to determine the correctness of Frerich's ex- 
planation of ursemic intoxication, by the conversion of urea into carbonate of 
ammonia, and resulting, among other conclusions, in the opinion, that tMs 
theory fails to be sustained, and tliat the carbonate of ammonia is not, itself, 
more poisonous than urea. 
In the brief discussion wMch. ensued, the fact, mentioned in the paper, of 
the non-appearance of ammonia in the breath after the injection into the blood 
of urea mixed with vesical mucus, was noted, as being contrary to expectation 
based on other facts. Dr. Hammond explained that, in his view, the conver- 
sion of urea into carbonate of ammonia, which occurs in the presence of mucus 
out of the body, will not take place in living blood. 
Dr. S. W. Mitchell remarked that healthy mucus has not been found to 
hasten this decomposition of urea ; but that, out of the body, urea will, with- 
out any ferment, undergo spontaneous conversion. 
Reduction of temperature by depletion. — Dr. S. W. Mitchell mentioned that, 
having occasion, recently, in a case of insanity, to take from a patient a very 
large amount of blood — 189 fluid ounces— in a short space of time, he observed 
*See N. Amer. Medico-Chiurg. Review, March, 1858. 
[April, 
