MICROSCOPIC ORGANISMS IN INTESTINAL CANAL. 261 
already mentioned, the resting conditions are represented by 
encysted zoospores or much more frequently by encysted amoeboid 
bodies. 
The following notes recorded in reference to the phenomena 
observed in a specimen of cow dung are generally typical of 
those in numerous other experiments of a similar nature. Some 
perfectly fresh cow dung was procured and set in a moist cham- 
ber at 10.30 a.m. The material was moist, faintly alkaline in 
reaction, and swarmed with large active zoospores. Five hours 
later a second preparation was taken from the specimen. In 
this an even greater number of active zoospores was present 
than in the first, and a certain number of still ones was also 
recognisable. A third preparation, procured seven hours later, 
showed no active zoospores but an abundance of still ones of 
oval and rounded form. After another interval of six hours a 
fourth specimen was taken and found to resemble the previous 
one in character save that a distinct contractile vesicle was 
visible in many of the cells. At this time (dawn) no signs of 
sporangia were visible, but a few hours subsequently they ap- 
peared in great abundance, while preparations of the basis showed 
an abundance of active ameboid bodies of various sizes, ranging 
from that of the still zoospores upwards. 
Similar phenomena repeat themselves with monotonous uni- 
formity in successive experiments. Again and again we find a 
basis abounding with zoospores; increase in the numbers of 
these bodies for some time; a cessation in their activity; the 
appearance of multitudes of bodies agreeing in size and form 
with the inactive zoospores, but characterised by the presence of 
a contractile vesicle; the emergence and growth of these as 
active amceboid bodies and the appearance of sporangia. That 
the latter are certainly the product of the union of the ameboid 
bodies is clear from the result of other observations, but, as 
necessarily is the case in all massive cultivations, the evidence 
connecting the zoospores originally present with the amceboid 
bodies subsequently appearing remains imperfect. That the 
relation is one of identity is, no doubt, rendered probable by the 
fact that the excreta in the fresh condition never show any 
proportion of ameeboid bodies or of still cellules capable of 
accounting for the enormous numbers subsequently present, 
unless an excessively rapid multiplicative division were assumed 
to take place from the scanty supply originally present. An 
assumption of this nature is, however, entirely devoid of any 
support from observation, as any division of the ameboid bodies 
previous to sporangic formation never appears to occur. On 
the other hand, we have the zoospores present in abundance 
from the outset, and capable of very rapid multiplication by 
