128 SUMMARY OF CURRENT RESEARCHES RELATING TO 
as before. To all of these media litmus may be added ; and their re- 
action should be slightly, but distinctly alkaline. 
The addition of litmus would seem to be valuable, not only as an 
indication of the reaction excited in the media, but also because it seems 
to possess some action protective of anaerobic bacteria. 
Urine-Agar for Cultivating Diphtheria Bacillus.* — Dr. H. Schlosser 
obtained very favourable results from using urine-agar for cultivating 
the bacillus of diphtheria, though the method has no superiority over 
that of Loeffler, who used blood-serum mixed with 25 per cent, grape- 
sugar meat-broth. 
Urine-agar is a mixture of 2 parts of meat-pepton-agar and 1 part 
sterile urine. Sterile urine was obtained by first washing the external 
meatus with sublimate, and then passing the urine into sterilize 1 test- 
tubes. The urine was used in this condition or was sterilized by heat- 
ing for half an hour to 70 o -80°. 
Growth of Cholera Bacilli on Potato.! — Dr. 0. Voges found that 
cholera bacilli inoculated on ordinary potato do not grow, but when 
2-8 per cent, common salt is added, the organisms develope freely. A 
very similar result to the latter is obtained when the potato is treated 
with 1/4-1/2 per cent. soda. The temperatures used in the experiments 
were 37° and 20°, and the only difference was that growth was less rapid 
at the latter. 
It would seem that the effective factor is the presence of sodium 
chloride rather than the chemical reaction, for the reaction of the potatoes 
treated with common salt was acid, and the others alkaline, the results 
being in both instances approximately equal. 
Isolating Bacillus of Diphtheria from Toys.j; — Dr. R. Abel adopted 
the following procedure for determining the presence of diphtheria 
organisms in a box of bricks which were suspected of being the source of 
contagion. After several unsuccessful attempts made by scraping the 
surface of some of the bricks and sowing the scrapings in blood-serum, 
agar, and bouillon, the whole lot of bricks were finally soaked for about 
half a minute in sterilized bouillon. 
Serum and agar tubes were inoculated with some drops of the 
bouillon. A guinea-pig was inoculated with 1 ccm., and the residue was 
incubated in a flask. On the third day after the inoculation the guinea- 
pig died with symptoms of diphtheria, and undoubted diphtheria bacilli 
were found at the inoculation site. Apparently only one serum-tube took 
with diphtheria, while in the bouillon diphtheria bacilli were found on the 
sixth day, and urine-serum subcultures from this bouillon showed diph- 
theria colonies. Some of this was mixed with salt solution, and 0 * 1 ccm. 
was injected into a guinea-pig, which died of diphtheria on the third 
day. lfound about the inoculation wound there was haemorrhagic oedema 
of the subcutaneous tissue, with considerable hypersemia of the skin, 
effusion in the pleural sacs, haemorrhagic consolidations in the lungs, 
catarrhal nephritis, swelling and redness of the adrenals. Pure culti- 
vations were obtained from the inoculation site, cultures from other 
parts remaining sterile. It was therefore concluded that the bricks 
were the source of the contagion. 
* Centralbl. f. Bakteriol. u. Parasitenk., xiv. (1893) pp. 657-G2. 
f Op. cit., xiii. (1893) pp. 543-50. X Op. cit., xiv. (1893) pp. 756-61. 
