CONTAINED IN PLANTS FOR ANIMALS AND MEN. 477 
exist numerous kinds of bacteria which can reduce the nitrates to 
the poisonous nitrites while other kinds of bacteria again reduce 
them directly to the less noxious ammonia. (l) 
The dangerous character of nitrites is clearly elucidated 
by the observation of Atkinson, that 0.2 g. sodium nitrite pro¬ 
duces heavy intoxication in men. (2) Guinea-pigs are killed by 
0.5 g. of sodium nitrite no matter whether administered through 
the stomach or subcutaneously, under the phenomena of paralys¬ 
is and kyanosis. 
Of those bacteria which produce nitrites from nitrates, the 
bacillus of Cholera asiatica acts most energetically, and Emmerich 
and Tsuboi have therefore propounded the theory that the 
symptoms in cholera disease are due to the nitrites formed by 
this bacillus in the intestines of men from the nitrates in foodl 3) 4 
Indeed, this theory explains thus far alone the temporal, local 
and individual disposition for cholera. (4) Pettenkofer pointed out 
that cholera in temperate zones makes its appearance as a great 
epidemic always late in summer or at the beginning of autumn, 
further that certain cities are never visited by this epidemic, and 
that drinking water has no influence upon the spread of cholera, (5) 
and inferred that there must exist a second principle besides the 
cholera bacillus to make the genuine cholera possible. 
(1) In. this regard an observation made by Richter is of great interest ; lie discovered 
nitrites in the urine in a case of acute affection (catarrh) of stomach and intestines, and 
elucidated further that the action of a coccus upon the nitrates of the food had given rise 
to the production of the poisonous nitrites. (Fortschritte, d. Med. 13. 478). 
(2) Certain animals as rabbits require more to affect them seriously ; perhaps there 
exists conditions in them by which the nitrous acid is prevented from being set free so 
easily. 
(3) Münch. Med. Wochenschr, 1893. That theory was attacked by Klemperer and 
Pfeiffer, but not disproved. By means of the reaction of Gries, nitrous acid would no 
doubt be discovered more often than formerly in the feces of cholera patients. 
For the production of the cholera-red reaction indol is necessary, but as Govini 
(1893) has shown this is not formed in presence of much sugar and is absent sometimes 
in cholera-feces. 
(4) Semerad came to the same conclusion as Pettenkofer, that besides meteorological 
conditions the soil has also great influence, as his investigations on the cholera-epidemic 
in Jungbunzlau left no doubt on this point. 
(5) The nitrates are present, if at all, in too small quantities to be taken into 
account : thus, the sum of nitrous and nitric acid in 10,000 parts of drink water of Tokyo 
(1885) was found to be : 
Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. 
0.002 0.004 0.158 0.173 0.21 ï 0.128 0.156 0.163 0.162 0.152 0.110 0.009 
