280 bD. D. CUNNINGHAM. 
dilatation and rigidity normal under such circumstances. They 
were circular, entirely or almost entirely motionless, the granular 
matter which they contained gathered into hard lumpy masses, 
and with a large sharply-defined clear vacuole, apparently a rigid 
contractile vesicle. Some of them showed a very instructive 
phenomenon. In such specimens vacuolar cavities containing 
spherical masses of bacterial spores were still present. The re- 
markable thing in reference to these was that in many instances 
a development of a new generation of active bacteria had occurred 
within them, active rods darting hither and thither in the peri- 
pheral fluid of the vacuoles, and knocking and turning about the 
persisting granular mass (Fig. 23), Interpreted in accordance 
Fic. 23. Development of Bacteria within digestive vacuoles of dying 
Ameba x 1000. 
with current theories of disease, this phenomenon would indicate 
that the Amcebe were dying, due to their infection with bacterial 
organisms ; whereas, in fact, there can be no doubt that the 
presence of the latter was really the result of processes of de- 
velopment in the ingested spores occurring after the Amcebee had 
been enfeebled or killed by the supervention of unfavorable con- 
ditions in the medium. ‘The Amcebz, as usual, were apparently 
slowly asphyxiated by insufficient access of air to the medium, 
and the bacterial elements within them now underwent develup- 
ment in place of digestion. They clearly had not invaded the 
amcebal body subsequent to its death, being confined solely to 
the digestive vacuoles of the interior, whilst the peripheral sub- 
stance remained entirely free from them. Moreover, the Amebe, 
in certain instances, appeared to be enfeebled rather than actually 
