1897 THE MICROSCOPE. 141 
Home again, I searched into the depths of the trans” 
parent jewel, but with no success. Such close scrutiny 
of the taw made it seem larger, and I tried to reason 
that the bubble, which had certainly moved before my 
eyes, had in some way worked out of the stone. After 
sup per, I resumed the inspection of the gem. Placing it 
in the forceps, turning on the light, and then giving the 
holder just a little turn there was my itinerant bubble 
again. The bubble was falling to pieces; and ina few 
moments it had entirely disappeared. Ata temperature 
between 29.5° and 30° C., the bubble changed from a 
liquid to an invisible gas. This is the critical point of 
liquified Carbonic acid when under a pressure of 90 
atmospheres. The sapphire is born among the old for- 
mations within the crust of the earth; and with this rev- 
elation we feel sure of many more points concerning the 
early life of a sapphire, through induction. 
Black Plague in China.—Jansen states that this disease 
is caused by a specific bacillus and that this organism 
occurs in dead rats and mice found in pest houses, also 
bogs. That Chinese should be affected with this terrible 
plague is not strange, since in many houses bogs form 
part of the household. Pigeons are immune. 
Kitusuta states that inasmuch as the general symptoms 
of the disease resemble those of anthrax, it is possible to 
distinguish it only by making a bacteriological examina- 
tion (Centralblatt.:Bakt. u Parasitenk. xix; Abth I 974.) 
Yellow Fever Microbes.— Dr. Havelburg announces 
that the microbe which he considers the specific cause of 
yellow fever is found only in the stomach and intestines, 
but is cultivated by injecting it subcutaneously into guinea 
pigs. He finds that a previous injection of blood from a 
yellow fever convalescent renders an animal immune toan 
otherwise fatal dose of injection of the cultivated microbe. 
| O Brazil Medico. 
