1854.] 205 



when it was again carefully washed and placed in the solution of the chloride of 

 calcium, where it remained for a similar length of time. Finally, it was re- 

 moved from this, back to the solution of the oxalate of ammonia. 



During the course of the experiment, which lasted four hours, the frog gradu- 

 ally became weaker and more inactive, and finally died in the solution of the 

 oxalate of ammonia in which it was last placed. The specific gravity of the 

 solution of the oxalate of ammonia was much less than that of the chloride of 

 calcium, consequently the object in moving the frog from one solution to 

 another, was to obtain as large a deposite of the oxalate of lime within its 

 blood-vessels and tissues as possible, by promoting the actions of imbibition, 

 endosmose, and exosmose. 



As a general rule, the rapidity of the action of endosmose is proportional to 

 the difference of the densities of the exterior and interior fluids. The effects of 

 this action, or rather of the membranes, upon the chemical substances passing 

 through, will be manifested by the change of physical form exhibited by the 

 precipitate of the oxalate of lime. 



Immediately after the frog had been removed from the solution of the oxalate 

 of ammonia, an incision was made below and to the side of its sternum, into the 

 cavity of the thorax and abdomen. The heart was found still pulsating. The 

 blood-vessels beneath the skin, upon the surface of the stomach and intes- 

 tines, in the muscular fold of the peritonoeum, and between the kidneys, ap- 

 peared thoroughly injected with blood, as if the animal had died of violent in- 

 flammation of all these parts. 



The blood from the heart and lungs was first examined under the microscope, 

 in which, with a magnifying power of 210 diameters, were seen innumerable 

 minute cubical particles, floating amongst the large elliptical blood capsules. In 

 the fibrous tissue between the epidermis and pectoralis major muscle, square 

 plates, cubical crystals, and parallelograms were seen, together with minute 

 particles, the largest of which appeared to be cubes. 



The mesenteric fold of the peritonoeum contained the same equi-lateral, equi- 

 angular plates, and cubical crystals. In the fascia of the thigh, besides numbers 

 of these, there appeared, also, beautiful octohedral crystals of the oxalate of 

 lime, similar in all respects to those formed when the intestines of a raccoon, 

 (Procyon lotor,) were filled with a solution of the chloride of calcium, and im- 

 mersed in a solution of the oxalate of ammonia. 



When the eggs of the frog were mashed, and their contents spread out on a 

 glass slide and examined under the microscope, they contained multitudes of 

 equi-angular plates, aud cubical crystals of the oxalate of lime. 



It is probable that the exterior fluids passed through the anus and cloaca into 

 the oviducts and ovaries, and finally by endosmose into the eggs themselves. 



In the fibrous tissue of the walls of the abdomen, in addition to the cubes and 

 octohedra, and equi-lateral plates, there appeared, also, delicately formed dumb- 

 bell and ellipsoidal crystals. 



When the plantar fascia of the foot was cut through, from the incision flowed 

 a fluid resembling the liquor sanguinis mixed with a little blood, which, under a 

 magnifying power of 210 diameters, contained beautiful octohedral and dumb- 

 bell crystals of the oxalate of lime. 



This experiment was repeated with slight variations, as to the length of the 

 time, and the density of the fluids, and in every instance, without any exception, 

 the results were the same. 



In one instance, the deposit formed within the blood and tissues of the frog, 

 assumed the form of delicate dumbbell and cruciform crystals of the oxalate 

 of lime. Figure 1. represents the appearance of these crystals and their rela- 

 tive size, when compared with the blood corpuscles. In another experiment 

 the blood from the ventricle of the heart contained large and perfectly formed 

 octohedra, with a few dumb-bell crystals, while the various tissues and muscles 

 contained chiefly delicately formed dumb-bells and crystals, and the aqueous 

 humor of the eye contained octohedral, and comparatively large acicular crystals. 



Figure II. represents the crystals from the blood of the heart. 



Figure III. those found in the tissues, and between the fibres of the muscles. 



