ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
585 
silk filament its firm hard character and grey colour. This “ lime ” is 
soluble in boiling water, and when cold sets to a greyish jelly, forming, 
according to Herr G. Marpmann, a good cultivation medium for many 
bacteria. Not only do air and water bacteria grow well on the silk 
glue, but mould fungi, and the peptonising organisms also, though the 
medium is but little liquefied by the latter. Owing to the fact that 
silk glue contains sulphur, it forms a suitable medium for the cultiva- 
tion of thiophilous bacteria. The addition of salt, sugar, or pepton to 
the medium is not necessary. 
Growth of Diphtheria Bacilli on different Media.* — Dr. G. Michel 
records the results of an elaborate series of experiments made for the 
purpose of comparing the growth of diphtheria bacilli on the following 
media : — Glycerin-agar. Loeffler’s bullock-serum, normal bullock-serum, 
Loeffler’s horse-serum, and normal horse-serum. Of these, Loeffler’s 
t Centralbl. Bakt. u. Par., l te Abt., xxii. (1897) pp. 259-73 (5 figs.). 
2 s 2 
