270 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Inspissated Must and the Cultivation of Fungi.* — Though grape 
must is especially suitable for cultivating fungi it has been little used, 
because it is only obtainable at certain times of the year and in small 
quantities. This inconvenience can be obviated, says Dr. J. Wortmann, 
by obtaining inspissated must, and he recommends that made from white 
grapes which has been filtered before concentration. The must is evapora- 
ted down to about one-fourth of its original bulk, and, when used, four 
vols. of water are added to one vol. of must. Owing to the large quantity 
of sugar present, about 65 per cent., inspissated must does not deteriorate 
and has the special advantage for experimental purposes of possessing a 
fixed composition (20 per cent, sugar, 0 • 24 per cent, acid, and 0 * 027 
per cent, nitrogen). The amount of nitrogenous matter is from one- 
fourth to one-half of natural must and if desirable may be increased by 
adding tartrate of ammonia when diluting. 
Plate Cultivations of Anaerobes.f — Dr. Arens uses the following 
simple but efficacious method for cultivating anaerobic organisms. A 
small exsiccator such as is found in every laboratory is nearly filled 
with a mixture of sand and pyrogallic acid, space being left for one or 
more small Petri’s capsules. The plates are made in the usual way, 
except that it is advisable that they should consist of the contents of 
two tubes instead of one. A sufficient quantity of 10 per cent, caustic 
potash is then added to the sand and pyrogallic acid mixture, the capsule 
is laid on the surface, and then the exsiccator, the lid of which must fit 
well and be greased, is closed. 
Detection of growth may be facilitated by covering the sand surface 
with blackened paper, and the absorption of oxygen hastened, when the 
plate has set, by just tilting up the exsiccator. As the absorption of air 
takes place quickly there is no fear either of the growth of aerobic 
bacteria before this has happened or of the suppression of anaerobic 
fungi owing to slowness of absorption. Of course, for cultivation purposes 
the whole apparatus is incubated. 
Method for Imparting Correct Reaction to Nutrient Gelatin.! — 
Dr. H. Timpe gives the following procedure for making nutrient gelatin. 
The meat broth is freed from albumen by boiling and then as usual 
mixed with 1 per cent, pepton, 1/2 per cent, cooking salt, and 10 per 
cent, gelatin. This mixture is for some time kept at a gentle heat until 
the gelatin is completely dissolved, and is finally allowed to boil. The 
boiling-hot solution is then treated with 25 per cent, caustic potash until 
a drop of it on a piece of filter paper moistened with an alcoholic solu- 
tion of phenolphthalein leaves a red-edged spot. When a small por- 
tion and a couple of drops of the phenolphthalein solution are brought 
together in a test-tube there should be a distinct red colour ; if not the 
alkali must be added drop by drop until the reaction occurs. This step 
must be taken with great care, for excess or defect of alkali results in an 
imperfect medium. Should the medium have cooled down too much 
during this process of neutralization it must be reboiled, but for a short 
time only as too prolonged boiling injures the property of gelatinization. 
The precipitate of calcium phosphate is rapidly thrown down in gelatin 
* Bot. Zeitung, li. (1893) p. 177. 
t Centralbl. f. Bakteriol. u. Parasitenk., xv. (1894) pp. 15-7. 
X Op. cit., xiv. (1893) pp. 845-52. 
