32 THOMPSON YATES LABORATORIES REPORT 
Tubercle Bacilli in Butter 
It has been proved by many authors that butter made from tuberculous milk was also 
infective ; and by Heim* and GASPERiNit that tubercle bacilli live and keep their virulence in 
butter for a period of even 1 2 da}'s. 
BrusaferroJ found virulent tubercle bacilli in i sample out of 9 ; Roth§ in 2 samples 
out of 20 ; SchuchardtII only in i out of 42 samples ; and GroningH in 8 (47 per cent.) out of 
17 samples. 
From the results of experiments by Rabinowitsch ** it is now doubtful whether the 
animals in the above-mentioned experiments (references 19 to 22) were infected with Koch's 
bacillus tuberculosis. She examined 30 samples of butter from Berlin and 50 from Philadelphia, 
and /« no single case found bacilli ' which, by means of culture and the pathological results of 
Guinea-pig inoculations, could be pronounced as identical with Koch's bacillus tuberculosis;' but 
' 23 samples (28.7 per cent.) produced changes which, both macro- and microscopically, resembled 
those of tuberculosis, but which by more extensive and exact examination could be distinguished 
with ease.' Other authors have described similar pseudo-tuberculosis organisms; Petri tt in 
milk, MoellerJJ in milk, in 'Timotheus' grass, and in fasces of cattle. The characteristics of 
Rabinowitsch's micro-organism are as follows : —It is immotile, and in form closely resembles the 
bacillus tuberculosis. The bacilli generally occur singly and are often slightly curved ; but when 
growing rapidly in tissue bacilli are often found lying parallel. Sometimes they form long 
unbranched threads, and sometimes are divided into short pieces. The bacilli are somewhat 
thicker than bacillus tuberculosis and often show a club-shaped swelling on one side. Spores are 
not formed, but one portion of the bacillus stains often more intensely than the rest. The bacilli 
stained by many methods of staining tubercle bacilli cannot be distinguished from the latter ; only 
by the employment of very dilute watery solutions of methylene blue could any distinguishing 
feature be observed, viz., that bacilli from a culture of bacillus tuberculosis stain only at one spot, 
the rest of the bacillus remaining unstained ; while in the case of bacillus pseudo-tuberculosis the 
whole bacillus stains faintly and generally uniformly, seldom showing a more deeply-stained part. 
Cultural differences, however, occur. On agar, the bacilli taken direct from an infected 
animal produce visible colonies on the second or third day. At first the agar surface is covered 
with a thick, moist, creamy layer : in old cultures by a folded membrane often orange- or copper- 
coloured. After repeated passages through animals cultures on agar or glycerine-agaf show a dry, 
brittle, crumpled membrane resembling that of bacillus tuberculosis. In plate cultures the deep 
colonies are grey in colour, round or oval, and uniformly granular. On the surface colonies are 
better developed, have a uniformly granular grey centre, and a clear wavy outer zone ; the surface 
of the colony is often dry and conical. On butter-agar in fresh cultures the colonies are small, 
* ' Arbeiten aus dem Kaiserlichen Gesunclheitsamte,' 
1889, Banti V, p. 294. 
■\ ' Giornale della Reale Societa d'Igiene,' i8go. 
J ' Giornale di Med. Vetev. Prat.,' 1890, p. 201. 
§ ' Correspondenzblatt fiir Schweizer Aerzte,' 1894. 
II 'Inaugural Dissertation,' Marburg, 1896. 
^ ' Ceiitralzeitung fiir Veteriniir-, Viehmarkts-, und Schlachthof- 
Angelegenheiten,' 1897, Nos. 14 and 15. 
' Zeitschrift fiir Hygiene,' 1897, p. 90. 
f-j- ' Arbeiten aus dem Kaiserlichen Gesundheitsamte,' 1898, 
Band xiv. 
XX ' Therapeutische Monatshefte,' November, 1898. 
