314 OFFICIAL REFUTATION OF DR. KOCH’S THEORY 
13. The only other evidence which has been adduced in 
favour of a causal connection between this organism and 
the disease is that acquired by means of experiments with 
animals. Referring to researches of this character which 
were performed by the German Commission and by other 
observers, as well as by themselves, Drs. Klein and Gibbes 
say: 
“ When in Egypt and Calcutta, Koch performed a large 
number of experiments by feeding, subcutaneous and intra- 
venous injection, as well as injection into the duodenum with 
rice-water stools and with pure cultivations of comma-bacilli, 
on rodents, carnivorous animals, and monkeys, and obtained 
no result, and his inquiries among the people led him to the 
conclusion that no case was known of a domestic animal 
having taken cholera, and he therefore came to the conclusion 
that cholera is not transmissible to the lower animals. He 
made, however, the observation that animals (rodents) may die 
of septicemia after inoculation with rice-water stools, and that 
the comma-bacilli are capable of multiplication within the 
animals inoculated, without, however, producing cholera. 
Since his return to Berlin he maintained that he has been able 
to confirm the assertions of Nicati and Rietsch—viz. that 
injection of the comma-bacilli into the duodenum of dogs and 
guinea-pigs led to death with multiplication of the comma- 
bacilli, and he therefore considers it proved that the comma- 
bacilli are pathogenic organisms. 
““A large number of experiments were performed by one 
of us on rodents, cats, dogs, and monkeys by feeding, by 
subcutaneous, intraperitoneal, and intravenous injection, and 
by injection into the cavity of the upper part of the small 
intestine of mucus flakes of the ileum of typical acute cholera, 
and of pure cultivations of choleraic comma-bacilli and the 
small straight bacilli; the results of these experiments are 
described in the following pages” (pp. 19, 20). 
“From all these experiments it follows that neither with 
mucus flakes taken from the ileum of acute cases of cholera 
nor with stools recent and old, nor with cultivations of comma- 
