416 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
sealed over in order to prevent the gelatin from drying. The disin- 
fectants recommended are 5 per cent, acetic acid, or 1 per cent, carbolic 
acid. The gelatin solution is of course a simple one, and without any 
additions ; it is clarified by means of egg albumen, and the acid added 
after filtration. 
By this method the author preserved cultivations for two years, 
but he admits that sometimes, for reasons inexplicable, the gelatin 
liquefies. 
Simplified Method for preparing Meat-Pepton-Agar.* — Mr. N. 
Tischutkin prepares and filters meat-pepton-agar in the short time of 
2-2J hours. The requisite quantity of agar is placed for 15 minutes in 
a dilute solution of acetic acid (5 ccm. acid. acet. glacial, in 100 ccm.). 
The swollen agar is then carefully washed free from acid and then 
mixed with bouillon. Boiling for 8-5 minutes suffices to make a perfect 
solution of the agar in bouillon. After neutralizing and cooling down 
the whites of two eggs are added, and the mixture placed for half to 
three-quarters of an hour in a Koch’s steamer. It is next filtered through 
Schulze’s paper. 
Preparing Nutrient Agar.f — Prof, van Overbeek de Meyer prepares 
nutrient agar in a very satisfactory manner by the aid of his disin- 
fection oven, which insures a constant temperature of 100° to 101°. The 
agar is cut up into very small pieces and in the proportion of 1 J to 2 per 
cent, is poured into O' 5 litre of Loeffler’s bouillon. To this is added 
1 per cent, pepton, and 0*5 per cent, common salt. 
After the lapse of about an hour, the mixture is placed in the disin- 
fection oven, and there steamed for three-quarters of an hour at 100°. 
This dissolves the agar and separates out the coagulable albuminoids. 
The next step is to neutralize or impart any suitable reaction to the 
solution, after which it is filtered through blotting-paper into flasks. 
The funnel is covered over with a glass, and the funnel, flask, and cover 
are again placed for three-quarters to one hour in the disinfection oven. 
In the end about O’ 25 litre of perfect bouillon -agar are thus obtained. 
If requisite any additional substances, such as grape-sugar, glycerin, &c., 
may be added, after w hich the mass is sterilized for half an hour, and 
the process repeated on the two following days. 
Cultivating Actinomyces.^ — Herren N. Protopopoff and H. Hammer 
cultivated Actinomyces on glycerin agar bouillon, potato gelatin, and 
in milk and eggs. The cultivations were derived from a pure cultiva- 
tion prepared by Prof. Afanassiew from the pus of a person affected with 
actinomycosis. 
By rubbing granules of the agar cultivation together with sterilized 
bouillon and inoculating with this emulsion, a much more rapid 
development was obtained than by direct transference of the granules. 
On glycerin agar the cultivation presented a mass of miliary granules, 
about the size of hemp-seeds, of a yellowish-white colour, and firmly 
* 'Wratsch, 1890, No. 8. See Centralbl. f. Bacteriol. u. Parasitenk., ix. (1891) 
p. 208. t Centralbl. f. Bakteriol. u. Parasitenk, ix. (1891) pp. 163-5. 
; Zeitschr. f. Heilk., xi. (1890). See Centralbl. f. Bakteriol. u. Parasitenk., ix. 
(1891) pp. 63-4. 
