252 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
matters are removed. To this mass may now be added a saline mixture, 
suitable for forming nitrites, and also calcium carbonate. The whole 
is then boiled to kill off any bacteria. This method is far simpler 
than the silicic acid method. The salt recommended to be added is 
NH 4 NaHP0 4 -{- 4H 2 0 in the proportion of 0*2 per cent. Besides this, 
chloride of potassium 0*05 is also inserted. The chalk makes the re- 
action neutral, or slightly alkaline. 
Gold Sterilising Bougie Filters and other Apparatus.* — MM. Couton 
and Gasser use two solutions for cold sterilising porcelain bougie filters, 
one a dilute solution of calcium chloride, the other a dilute hydrochloric 
acid. Neither solution need be prepared afresh every time, but can be 
used for ten purifications. The bougies are placed in each solution for 
a quarter of an hour, first in the eau de Javelle, and afterwards in the 
acid. The calcium chloride decomposes the albuminoid substances 
which block up the pores ; the hydrochloric acid afterwards unites with 
the calcium, and chlorine is set free. This gas decomposes the im- 
purities, and the process is finished by washing out with pure water. 
Bougies which had previously given 1-2 litres per hour, after having 
been treated by the cold purifying procedure, gave 9-12 litres. The 
bougies remained germ-free for 10 days; after 28 days there were 
880-1310 germs per ccm. 
Apparatus for Bemoving definite Quantities of Fluid Cultivation 
Media.t — Dr. R. Kretz has devised a very simple and easily sterilisable 
Fig. 53. 
apparatus for drawing off small quantities of bouillon, &c., in an exact 
and facile way. The apparatus is merely a siphon with intermitting 
* L'ev.Td’Hygiene, 1895, 17, 4. See Centralbl. f. Bakteriol. u. Parasitenk., 
1“ Abt., xix. (1896) p. 299. 
t Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., xix. (1896) pp. 73-4 (1 fig.). 
