128 
R. KOCH. 
the bacill-bearing substance cannot be so crushed that the bacilli can be spread out 
free and upon the surface of the blood serum ; on this account they remain hidden 
in the substance, develop there and the colonies growing in scanty numbers with¬ 
draw themselves easily from observation. 
The reinculturen succeed most surely when a tubercle rich in bacilli, or 
richly tuberculous substance from the interior of a still slightly caseous lymph- 
gland of a guinea pig killed for the purpose, be used for sowing. For this pur¬ 
pose one should proceed in the following manner : A number of knives, scissors 
and pincettes are so thoroughly heated in the flame that they are freed from all 
bacteria clinging to them, and laid ready in such a manner that no impurities can 
afterward get at them. In the mean time, the animal, which must just have 
been killed, is spread out upon a dissecting board. In order, when cutting 
through the skin to avoid dusting off particles of dirt, hairs, etc., the fur of the 
animal should be thoroughly moistened with a one per cent, strong sublimate 
solution. After this one cuts through the skin with the still hot scissors and with 
the help of the still hot pincette, and lays it back on both sides so far that the 
lymph-glands of the regio axillaris and inguinalis are completely free, but the 
glands, if they are to be used for reinculturen, must not be touched with the in¬ 
struments used in cutting the skin. With another hot pair of scissors another 
piece, 1-2 qu. ctm. large, is cut out from the side wall of the thorax, and the 
surface of the lungs laid bare. By this means a number of little tuberculous 
knots are made accessible, from which, as quickly as possible, with still other 
instruments, which must have been cooled for this operation, one or more are 
prepared. In order to free the bacilli contained in the little knots, one cuts or 
crushes these with the scissors or, still better, between two scalpels which have 
been previously heated and cooled. The substance broken and rubbed to pieces 
is then put into the re-agent glass, spread out upon the surface and rubbed with 
a platinum wire which has been melted into a glass staff, and has immediately 
before using been heated and cooled again. The re-agent glass is to be held 
slantingly or almost horizontally between the thumb and the forefinger, and the 
wadding cork must be so held in the mean time with the other fingers of the 
hand that impurities from coming in contact with other objects may not 
reach it. The placing of the substance on the stiffened serum which, for the 
sake of brevity may be called inoculation, must be done as quickly as possible in 
order that the germs of foreign organisms from the air may not get upon the in¬ 
oculating substance, or into the re-agent glass. It is also advisable to undertake 
the experiment in a room in which no dust is stirred up, and moreover all un¬ 
necessary motions which could cause dust from clothes, etc., to get into the air 
are to be avoided, since experience has taught that the germs of micro-organisms 
cling to the particles of dust suspended in the air. 
In spite of all these prudential measures the entrance of single foreign germs 
is not to be avoided with absolute certainty, and it is necessary in every single 
case to inoculate several re-agent glasses, perhaps 5-10, that if the reincultur 
does not succeed in the one or the other, the remainder may be free from all im¬ 
purities. 
In such manner as the preparation of lung tubercles for sowing has been de¬ 
scribed, must the experiments be conducted when lymph-glands, tubercles of the 
