476 OBSERVATIONS ON THE INFLUENCE OF CHOLERA. 
cholera poison is deleterious to plants, as well as to the lower 
animals and to man ; but the whole subject is one that still 
remains open to rigorous investigation, including minute 
chemical, histological, and microscopical examination. Dr. 
Lindsay concludes by propounding a very elaborate system 
of investigation, by veterinary surgeons, grooms, horse- 
breakers, poultry-men, and others, as well as by the medical 
profession ; and, from the mass of facts accumulated by 
numbers of observers, it may be hoped such general prin- 
ciples may be established as shall throw some light upon the 
nature of this mysterious scourge. 
Dr. Snow thought there was no ground for believing that 
the cholera attacked the lower animals and plants. The grape 
disease was caused by a certain fungus, and the diseases of 
wheat arose from insects having no connexion with cholera. 
The nature of the potato disease was unknown. The disease 
was not recognised till 1846 , sixteen years after the first 
epidemic of cholera, two years after the second, and seven 
years before the third. The author stated, that cholera epi- 
demics were coincident with a heavy and moist state of the 
atmosphere; but in the autumn of 1849 , and also in 1854 , 
when there was the greatest mortality, the air was drier than 
usual. He (Dr. Snow) was disappointed that the author had 
not adduced more facts. His impression was, that there was 
no fatal disease prevalent among animals contemporaneously 
with cholera epidemics. 
Dr. TFeber said, that in 1849 he mixed the contents of the 
intestines of a cholera patient with some food which he gave 
to five dogs and six cats. One of the dogs only (about five 
days old) died; and there were no symptoms referable to 
cholera. 
Dr. Greenhow agreed with Dr. Snow in thinking that cholera 
did not affect the lower animals. 
Dr. Me William observed, that Dr. Lindsay’s excellent paper 
w r as suggestive, rather than didactic, to labourers in this 
interesting field of investigation. The cleverest account he 
had seen of a cholera epizooty being coincident with a cholera 
epidemic in man, was that recorded by the Faculty of Medi- 
cine at Vienna, which had been alluded to by Dr. Lindsay. 
It had been said that the lower animals became affected when 
other epidemics were prevailing among men. For instance, 
it was asserted, that because horses, donkeys, and goats, died 
in great numbers in the Cape de Verds, during the prevalence 
of yellow fever at Boa Vista, there w r as some connexion be- 
tween the epizooty and the epidemy. This, however, w 7 as 
not the case ; for the mortality among the lower animals was 
