550 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
3. Technique.* * * § 
Cl) Collecting: Objects, including: Culture Processes. 
Culture of Diatoms.f — In his concluding paper on this subject, Dr. 
P. Miquel describes several forms of cells which he has found convenient 
for preserving diatoms alive, and for propagating, observing, and 
photographing them. He has succeeded in keeping some species alive 
for as long as ten months, watching all the various stages of propagation 
as far as the production of auxospores. 
Cultivating Ascospores on Clay Cubes.J — Dr. H. Elion recommends 
cubes of clay 2 by 2 by 2 cm. for cultivating ascospores. These cubes 
are easily sterilized, and the ascospore formation which takes place on 
them is very satisfactory. The author finds they are superior to the 
gypsum blocks. 
Growing Tubercle Bacilli on Vegetable Nutrient Media.§— Dr. 
Sander finds that the tubercle bacilli of mammals will grow, not 
only on potato, as was first pointed out by Pawlowsky, but in various 
other vegetable media, such as carrot, turnip, radish, and macaroni. 
On the three first media the growth presented the appearance of chalky 
white nodules, while on macaroni it was almost invisible. Hence it is 
possible that baker’s bread, &c., may sometimes be the source of infection. 
The reaction of these media is not so restricted as it is for those of 
animal origin ; indeed a slight degree of acidity appears to be not only 
beneficial but requisite. Access of air to the cultivation appears to be 
necessary. The most favourable temperature is rather high, viz. from 
38°-39°. At 22°-23° no growth took place. The carrot, turnip, and 
radish were used as solid cultivation media after the manner of potato 
cultures in tubes, while the macaroni was soaked and then stuck on 
slips of glass, which were dropped into the test-tubes. The tubercle 
bacilli were found to grow also in fluid media made from potato. The 
juice obtained from mashed potatoes was decanted, and then placed in a 
water-bath for one hour. From this experiments were made showing 
that an acid reaction was necessary. One part was neutralized with soda, 
and after filtration, both were sterilized. Further, to another portion of 
each was added 4 per cent, of glycerin. The growth was strongest in 
the acid glycerin potato soup. 
The author also states that under some circumstances the tubercle 
bacillus thrives in sterilized tap-water, and that the presence of mould 
does not prevent this development. In vegetable media the growth will 
usually be found to be more luxuriant and more rapid than in animal 
media, these properties becoming still more marked in the second and 
third generation. 
Certain spheroidal bright bulgings occurring at the end of the bacilli 
* This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes; 
(4) Staining and Injecting; (5) Mounting, including slides, preservative fluids, &c. ; 
(6) Miscellaneous. 
f Diatomiste, i. (1893) pp. 165-72 (3 figs.). Cf. this Journal, ante, p. 111. 
% Centralbl. f. Bakteriol. u. Parasitenk,, xiii. (1893) p. 749. 
§ Arch. f. Hygiene, xvi. No. 3. See Centralbl. f. Bakteriol. u. Parasitenk., xiii. 
(1893) pp. 732-3. 
