130 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
posed. The flasks were inoculated with one or more frustules isolated 
by means of a capillary tube. 
Miquel’s Cell for Pure Cultures of Diatoms.* — Dr. H. van Heurck 
describes Miquel’s cell for the pure cultivation of diatoms. To a slide 
having a circular hole 2 mm. in diameter towards its upper side is fixed 
a ring, and to the ring a circular cover-glass. In this way is made a 
cell with a lateral aperture, which can be held vertically or horizontally. 
The slide is allowed to rest during the cultivation on the cover-glass 
upon which the deposits form, and hence these cultures maybe examined 
with the highest powers. 
Fjg. 6. 
L 0 L 
M M 
Fig. 5. 
Fig. 5. — Transverse section of cell: L L, slide; D, aperture of 2 mm.; 
c c, ring ; MM, cover-glass ; E, cultivation fluid. 
Fig. 6. — Longitudinal section : O, aperture. 
Fig. 7. — View of cell from Microscope bent at an angle. 
Cultivating Gonococcus.! — Dr. A. Wassermann has found that 
Gonococcus grows best on a medium which contains uncoagulated serum- 
albumen and pepton. The coagulation of the serum by boiling is pre- 
vented by the addition of casein-sodium phosphate (nutrose), a substance 
which also promotes the growth of Gonococcus. The medium is made 
by putting 15 ccm. of pig’s serum in an Erlenmeyer’s flask, diluting 
with 30-35 ccm. of water, and then adding 2-3 ccm. of glycerin, and 
finally 0*8 grm. (2 per cent.) of nutrose. The flask is then well 
shaken in order to properly mix the ingredients, after which it is heated 
to boiling. It is sterilised in 20-30 minutes. The sterilised solution 
may be kept in this condition for future use, and suffices for 6-8 plates. 
When required for use, a number of 2 per cent, pepton-agar tubes are 
liquefied and mixed in equal parts with the serum fluid, and the mixture 
poured into Petri’s capsules. When set, the medium is ready for use. 
The serum and agar must be mixed at between 50° and 60°. If the 
pig’s serum is very rich in albumen, it is advisable to mix the 15 ccm. 
with 40 ccm. of water instead of 35 ccm. 
* Zeitschr. f. angew. Mikr., iii. (1897) p. 230. 
f Berlin. Klin. Wochenschr., 1897, p. 685. See Centralbl. Bakt. u. Par.. l te Abt., 
xxii. (1897) pp. 486-7. 
