( 647 ) 
When the white variants of the normal form are cultivated at 
30' C. in bouillon or in malt-wort, the cultures will, after a few 
re-inoculations, turn slimy like those of the red normal form itself. 
Colony culture on bouillonagar. proves that white slime variants are 
thrown off, in the same wav as the normal form throws off the red 
ones. The white slime variants (N°. 7 ? and 14) correspond by the 
nature of their colonies to the two white forms, albus (4) and albus 
hyalinus { 5), considered above. 
There is still another method to obtain the colourless slime variant 
from the red one. If this latter is cultivated at 30’ in malt-wort 
or in bouillon, we find after one or two transferrings, each time 
after two days, and when sown on bouillon-agar, many white slime 
colonies together with the unchanged red, moreover a considerable 
number of quite normal, not slimy red colonies, N“. 1, which 
is to be considered as atavism, but an atavism reposing on the loss 
of a character. The white slime variant, thus obtained by minus- 
variation, and found, in the table as K°. 7, seems identic with the 
one produced by plus-variation from the not slimy white variant, 
which latter for that reason has not been specially mentioned. 
Already in my earlier paper I spoke of rose variants, which so 
to say, keep the middle between the normal form and the white variant. 
They may be produced in various ways, for instance, by cultivating 
the normal form on plates of pure gelatin dissolved in distilled water 
(H,0, 10% of gelatin) at room temperature, at which rapid growth 
and vigorous melting occur. By daily streaking off on a bouillon 
agarplate the same colony obtained on such pure gelatin, and provided 
the temperature be kept between i4° and 17° C., we find, on the 
fifth or sixth day, the first rose variants, either or not with the 
white, which under these conditions appear later. Two rose variants 
(table N°. 2 and 3) are easily distinguished, but it is possible that 
there are many more whose perception is beyond the reach'of our 
observation. In any case, it is a fact that the character: “the 
faculty of producing pigment”, is divisible in many ways. The here¬ 
ditary constancy of at least one of these rose variants proved not 
to differ from that of the normal form. 
Another method to obtain rose variants is cultivation of the 
normal form in bouillon, which by evaporation has been reduced 
to a threefold concentration. After a single transport already, a 
large number of rose variants (3) had appeared by the side of 
normal forms; by a much lighter colour they showed a disposition 
to lose their colour entirely. The variability of the different rose 
variants is not the same; the form, obtained by the concentration 
