150 
K. KOCH. 
more or less swollen to a spindle shape, and the smaller younger colonies are ex¬ 
traordinarily thin and delicate, the older thicker and of heavier forms. Gradually, 
by continued spreading and melting together, the windings take more and more 
a plate-like form which, by the ware-like designs and the transition of their bor¬ 
ders into the peculiar oscillating lines of the single colonies, allow their origin as 
such to be recognized. Finally a number of such plates melt into each other, 
and form the previously described membrane-like bacilli colonies, while the plates 
proceeding from single colonies correspond with the whitish scales visible to the 
naked eye. In order to examine the colonies directly under the microscope and 
to follow tlielr development, four-cornered little glass basins provided with a 
glass cover are specially adapted. 
That these colonies are only formed by the tuberculous bacilli is soon seen 
when they are colored by Ehrlich’s method, and examined by strong magnifying 
power. This can be done most practically when one presses a covering glass 
firmly to the surface of the serum covered with colonies and takes it up again* 
Numerous colonies then remain clinging to the covering glass in their natural ar¬ 
rangement and grouping, dry there and can be colored as was described formerly 
in the directions for covering glass specimens. The bacilli are not thrown together 
without method, but are placed with their axes of length parallel with the axis 
of length of colony. It is striking that the bacilli do not touch each other, but 
% 
are separated, though only by slight spaces. As was formerly suggested, one 
may conclude from this conduct that the bacilli are surrounded by a building 
substance and are joined together by this, as is proved by the firm coherence of 
the colonies. Very frequently in farther advanced colonies one finds all or 
nearly all the bacilli spore-bearing. 
Usually the “ culturen ” have reached the maximum of their development 
after four weeks and then remain unchanged. The continuation of the same is 
most practically carried on in intervals of from two to four weeks. Nevertheless 
such “ culturen ” as have existed for months are still capable of development and 
can be used for further breeding. By the method described in the above I have 
gained a number of reinculturen of tuberculous bacilli from different materials, and 
have continued them through a longer or shorter succession of breedings. Several 
attempts at “culturen,” and indeed the first which were made, proceeded from 
guinea-pigs, which were tuberculously infected by inoculation from man and from 
various animals. Other “ culturen ” have been obtained directly from the original 
tuberculous material. The reinculturen indirectly gained by the help of the orig¬ 
inal inoculation of guinea-pigs relate to the following cases : 
1. —Human lung-phthisis cultivated through twenty-two months, therefore 
almost two years, in thirty-four successive breedings ; 
2. —Human lung-phthisis (caseous mass from the lung) cultivated for two and 
one-half months in five successive breedings ; 
3. —Human lung-phthisis (contents of the lung cavity) cultivated for three 
months in six successive breedings ; 
4. —Human miliary tuberculosis (tubercle of the lung) cultivated for seven 
mouths in twelve successive breedings; 
5. '—Human miliary tuberculosis (tubercle of the pia mater) cultivated for 
three months in five successive breedings ; 
