350 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
figures at each end indicate the percentage. The percentage volume is 
easily read off by resting the turned-over edge on the top of the closed 
arm of the tube, and moving the apparatus along until the lower edge 
rests on the neck connecting the arms. The apparatus, though chiefly 
intended for Dr. Th. Smith’s fermentation tube, might be used for other 
similar apparatus. 
Incubator for Maintaining Constant Low Temperatures.* — Dr. 
E. H. Wilson and Mr. R. B. E. Randolph have devised an apparatus 
for maintaining a constant low temperature (20° C.), adapted for work 
involving the use of gelatin and for storing stock-cultures and media. 
The apparatus consists of an ordinary incubator enclosed in a wooden 
box. On the top of the box is an ice-tank, from which the ice-water is 
distributed in a uniform manner over the inner chamber. When the 
temperature gets too low, an electric regulator brings into action an 
electric stove; and when the temperature gets too high, another contact 
cuts off the heat. The regulators are so adjusted that the critical 
interval is quite short, allowing only a maximum variation of 0*5° C. 
Detection of the Nectary in Flowers.! — Prof. P. Knuth finds that 
a very useful mode of determining the position of the nectary in flowers, 
i.e. of the exact spot where the excretion of sugar takes place, is to boil 
the entire organ either with Fehling’s solution, or with Hoppe-Seyler’s 
sugar reagent, ortho-nitro-phenol-propiolic acid ; in the latter case a deep- 
blue deposition of indigo takes place in the presence of grape-sugar. 
He describes the localisation in this way of the nectary in a number of 
flowers. 
Heavy Fluid suitable for Separating Mineral Mixtures.! — P° r 
the fluids composed of iodine, mercury, cadmium, &c., which suffer from 
the common fault of being easily decomposed, Herr Muthmann has had 
the good fortune to obtain a good substitute in acetylen tetrabromide. 
It is a colourless compound which boils at 137° C., and possesses a 
specific gravity of 3 * 0011. The fluid is insoluble in water ; it is soluble 
in ether, with which mixtures of any desired gravity can be prepared. 
Antitoxic Action of Carmine. § — Dr. Stoudensky states that when 
powdered carmine is mixed with tetanotoxin, the action of the texin is 
suspended. The fluid used consisted of carmine in physiological salt 
solution and tetanotoxin. The antitoxic action is lost if the carmine 
solution be heated to 100°-120°, or if alkali be added. 
If the carmine-toxin mixture be filtered, the filtrate contains no toxin. 
But though the carmine has fixed the toxin, the latter is not destroyed, 
for it may be extracted by maceration in distilled water. The antitoxic 
effect of the carmine is stated to be due to phagocytosis, as there is a 
smart reaction at the injection site. Here leucocytes accumulate and 
englobe the carmine particles, and along with these no doubt the toxin, 
which, though not chemically destroyed, is rendered inert. 
* Brooklyn Med. Journ. See Micr. Bull., xvi. (1899) pp. 1-4 (2 figs.). 
t Bot. Centralbl., lxxvi. (1898) pp. 76-83. 
X Zeitsclir. f. Krypt. (Munchen), xxx. p. 73. See Zeitsclir. f. ang. Mikr., iv. (1898) 
pp. 213-4. § Ann. Inst. Pasteur, xiii. (1899) pp. 126-8. 
