150 THE VENOMS OF CERTAIN THANATOPHIDE^E. 



animal was placed on its right side upon a thin oblong wooden board. On one 

 side of the board near the middle was cut a triangular opening, each side being 

 about one inch in length. An incision was then made in the median line through 

 the abdominal integuments, sufficiently large to allow a loop of the intestine to be 

 extracted. Care was taken that pressure should not interfere with the circulation. 

 The loop being drawn out, it was stretched over the hole in the board above described, 

 and kept in position by means of pins. 



The venom was applied to the uninjured surface of the mesentery. A saturated 

 aqueous solution of the dried venom was most commonly used. The moist chamber 

 was not required, as the experiments were of short duration. The warm stage 

 seemed only to hasten the process and otherwise was observed to have no special 

 influence, being rather disadvantageous. 



Experiment 1. — A young kitten was secured by means of ether as above described, 

 and placed upon the microscopic stage. A few drops of an aqueous solution of the 

 venom were allowed to flow over the mesentery. The part being carefully watched 

 with the naked eye, it was noticed that after one minute tiny hemorrhagic points 

 made their appearance here and there, all over that'part of the mesentery which 

 was under the direct influence of the venom. These hemorrhages increased rapidly 

 in size, and in a few minutes the whole surface became the seat of one diffused 

 hemorrhagic infiltration. (Plate III., Figs. 3, 4, 5, 6, 7.) 



Experiment 2. — Young white rat. Ether. Aqueous solution of venom applied 

 as before to the mesentery. The loop of the mesentery acted upon was quickly 

 cut out by means of scissors after the lapse of one minute and subjected to drying. 

 A beautiful preparation was thus obtained, in which the minute hemorrhages were 

 permanently fixed by drying, preserving their natural appearance. 1 



Experiment 3. — Young kitten. Chloral. Mesentery spread upon microscopical 

 stage. An aqueous solution of dried venom applied in the same manner as above. 

 In this case the hemorrhages did not appear so promptly and were not so rapid in 

 their development. Nearly five minutes elapsed before they began to form. 



Experiment 4. — Young white rat. Chloral. Venom applied as in preceding 

 experiments ; there seemed to be delay in the appearances and development of the 

 hemorrhages. 



Further enumeration of this class of observation is unnecessary, as more than 

 forty experiments exhibited the characteristic hemorrhages, except in the case of 

 frogs. Five of the latter were used. 



It was noted that chloral always retarded the production of hemorrhages, at 

 least they did not appear as rapidly as when ether was used. 



Microscopical Details, — It being necessary to study the exact location of the 

 hemorrhages and the mode of the escape of blood, the following modifications of 

 methods were adopted in repetition of the older experiments of Dr. Mitchell. 



1 After much experimentation this method of preparing permanent specimens was found to be the 

 only available one. Specimens of mesentery mounted in any kind of liquid very soon lose their 

 proper appearance, as the hemorrhagic specks in the membrane gradually vanish, or get blurred from 

 the effects of the preserving fluid. 



