1901] MICROSCOPICAL JOURNAL 203 
powers to human blood, not only in a fresh state, but 
also when dried and redissolved in normal saline solution. 
Ape’s blood was the only other one which behaved like 
human blood. Washermann and Schultze proceed thus: 
Dissolve the spot of blood to be examined in a little nor- 
mal saline solution ; filter ; place 4 or 5 c.cm. in two small 
test tubes, to one of which (a) add 0.5 c.cm. of rabbit’s 
blood made hemotoxic as above ; to an other (b) add 0.5 
c.cm. of normal rabbit’s blood. A third control tube (c) 
may be made with 4 or 5 c.cm. of solution of the blood of 
any animal] save ape or man in distilled water. Place the 
solutions in a thermometer at 37 deg. C.; if the spot of 
blood be human, in an hour’s time the tube (a) will show 
a turbidity or a floculent precipitate, while (0) and (c) will 
be perfectly limpid. Tarchetti carried out similar experi- 
ments with human blood and that of animals, both fresh 
and dried, for more than two months on cloth, wool, and 
knife blades, and found the method reliable. The reac- 
tion occurs almost as well at the air temperature as at 37 
deg. C. The solutions must be absolutely clear to begin 
with, and he finds distilled water better for this purpose 
than normal saline fluid, for it brings all the hemoglobin 
out of the corpuscles. He has found that the diagnosis 
can be at once made with the greatest certainty in a hang- 
ing drop under the microscope; a slight uniform precipi- 
tate is at once formed, and in a few minutes is seen as 
islets united in a reticulate pattern much resembling the 
- arrangement of Eberth’s bacillus agglutinated by typhoid 
serum. The same thing is observed in filtered aqueous 
solutions of dried blood. It is only after a long time 
(twelve to twenty-four hours) that a similar appearance 
is seen in blood of other animals. 
CEMENT TO STAND Spirit.—Dissolve 12 grains of gelatine 
(previously allowed to swell up in cold water) in 2 oz of hot 
water. Add to this sufficient fresh fine plaster of Paris to 
make upathick cream. Apply this at once to the metal 
