( 486 ) 
ated for 1 mgr. of the original contents, showed by means of culture- 
method 2.660.000 living organisms. If the small number of living 
bacteria present in the small intestine in absence of ingesta, is taken 
into consideration it is commonly possible, either by plate culture 
or by different dilutions in bouillon, to determine the number of 
these living bacteria. 
In rabbit no. 8 (Tab. III), without ingesta in the small intestine, 
quite the same relations are observed. Probably the Ileum here 
already for a long time contained no ingesta; hence the sterility- 
index is higher than in the former case. The Duodenum and Jejunum 
which have undoubtedly already for a longer time been free from 
ingesta possess a still higher sterility-index. In the Coecum, Processus 
vermiformis, and Colon adschendens the sterility-index again rises 
much, whilst in the rest of the large intestine and the Rectum again 
decomposition of dead organisms has taken place, and, in relation 
to the rate of solid substance, neither increase nor diminution of 
living bacteria has occurred. (Table IV, p. 483). 
If ingesta are present in the superior portion of the small intest- 
ine, the sterility-index is of course very low; the second part of the 
small intestine which for a longer time already contained no ingesta, 
shows a very high index. In the Coecum the index is again many 
times higher than in the whole small intestine. 
If ingesta are present in the Ileum, whilst Duodenum and Jejunum 
are devoid of them, (Tab. V, VI and VII), these ingesta prove 
still to contain a great number of living organisms; the sterility- 
index is then low there; in the Coecum, Proc. vermiformis, and 
Colon adschendens it is, however, always higher than in the whole 
small intestine. As the ingesta from the second part of the small 
intestine arrive at the Coecum with a relatively low index, the 
dying of living bacteria there is. evidently much more considerable 
than might be supposed from the comparison of the sterility-index 
of the Coecum with that of the whole small intestine, especially if 
the latter contain no ingesta at all. 
Accordingly the bacterial population in the intestinal canal] of 
the rabbit has the following course. With the ingesta large numbers 
of living and dead bacteria come from the stomach into the small 
intestine. As they move on, a number of living bacteria that have 
remained in the parts of the small intestine devoid of ingesta, 
die off, without these parts, however, becoming altogether sterile. 
When the ingesta have entered the large intestine the same process 
takes place in the inferior part of the small intestine. Furthermore, 
in the Coecum, Processus vermiformis, and Colon adschendens there 
