Hie Tuherde Bacillus. 
91 
cultures on glycerine-agar-agar the number of granular or 
beaded bacilli increases, and there are also numbers of peculiar 
forms. These are long bacilli, in some cases two or three times 
the length of an ordinary bacillus, provided with a club-shaped 
enlargement, and in other cases bacilli with short lateral 
branches (see Plate III., fig. 1). The bacilli with swollen 
extremities and the branched fonns were first observed by Nocard 
and Ronx. In milk the appearance is very striking, many bacilli 
attaining in old cultures a great length, and all are more uni- 
formly beaded than in any other cultivations (see Plate III., 
fig. 2). In old cultivations we can observe the formation of 
spores or seeds both in stained and unstained preparations. In 
the latter case they are recognised in the form of one or two 
highly refractive bodies in the individual bacilli. 
Chemical Phoducts of the Bacillus. 
To understand the formation and effects of the chemical 
products of the tubercle bacillus, it is necessary to briefly refer 
to a most important branch of pathological chemistry. So long 
ago as 1822, Gaspard and Stick discovered an intensely poisonous 
substance in extracts of the dead subject. In 18oG, Panum 
found a poison in putrid material ; later, a crystallisable poison, 
sejjsm, was obtained from putrid beer, and a venomous nitro- 
genous body from putrid meat.. This subject did not attract 
very much attention until the classical researches of Selmi. 
Selmi, in a celebrated poisoning case, demonstrated the presence 
of an alkaloid as the result of post-mortem change ; up to 
this time the discovery of an alkaloid in the body after death 
was considered as a proof of a poison having been administered 
during life. This stimulated the investigation of these newly 
discovered poisons, and the researches of Gautier and Selmi 
established the fact that albuminoid substances undergoing 
decomposition ^ give rise to the formation of animal alkaloids. 
These animal alkaloids Selmi named ptomaines, from ptoma, a 
dead body. Brieger, finding that the products of putrefaction 
were less poisonous than the products of pathogenic bacteria, 
suggested the name toxines to distinguish the latter. 
Ptomaines, or animal alkaloids, have been divided into two 
classes : those which are non-oxygenous, liquid, and volatile ; 
and those which are oxygenous, solid, and crystallisable. 
• Decomposition, or putrefaction, is the result of the growth of septic 
bacteria. 
