1901] MICROSCOPICAL JOURNAL. 147 
ganisms. It has been suggested for certain plants that 
the converting of free nitrogen and simple nitrogen com- 
pounds into the more complex forms used by the plant is 
due to the nostoc. And the writer suggests the possibil- 
ity of the use of nostoc forms in the cycads in the assis- 
tance of nitrogen assimilation. The tubercles then, have 
two functions, that of aerating, and that of assisting in 
nitrogen assimilation. (Bot. Gaz. 31 ; 265.) 
MICROSCOPICAL MANIPULATION. 
New METHOD oF Examinine Sputum.—Lanuoise and 
Girard (Arch. gen. de Med.) recommended the following 
method of examining sputum suspected of containing tu- 
bercle bacilli. It is based on the property possessed by 
the alkaline hypochlorites of dissolving mucous matter 
without the aid of heat. The sputum is put into a coni- 
cal vessel, and covered by about 10 times its volume of a 
33 per cent solution of chlorinated soda, and the whole 
well stirred up. It is then set aside for 24 hours, being 
given an energetic agitation from time to time. The dis- 
engagement of chlorine commences at once, and in 20 
minutes globules of mucus and of pus (should the latter 
be present) are dissolved, the liquid becoming more or less 
turbid from the matters held in suspension. At theend 
of the time named, however, the suspended matter will 
have settled in the conical point and the supernatant clear 
liquid may be drawn off with a pipette. If a centrifugal 
separator is at hand, the operator can, of course, save 
himself the delay by operating on a single tube several 
times, decanting each time. When the volume of the ma- 
terial has been reduced to 2 or 8 c.c. there is added 5 or 
6 drops of normal solution of sodium or potassium hy- 
drate, (40 grams of NaOH or 56 grams of KOH to the 
liter of water). This transforms the residual chlorine into 
a chloride of sodium or potassium, as the case may be. 
