F. C. MINETT AND M. R. DHANDA 309
that in his experiments urine, blood or hay infusion were added to the soil,
that all the materials were sterilized by heat and that the methods used, being
based merely on microscopical appearances, would now-a-days be considered
hardly sufficient. While his conclusions may have been correct in the cir-
cumstances, his work certainly does not support the contention that the orga-
nism can multiply in soil under natural conditions.
In a publication from the United States Department of Agriculture,
written by Salmon and Theobald Smith [1904], it is said, 'Meteorological
conditions also have an important share in determining the severity of the
disease. On these tracts subject to inundations in spring, a very hot, dry
summer is apt to cause a severe outbreak. The relation which the bacillus
bears to these conditions is not positively known. It may be that during
and immediately after inundations or in stagnant water the bacilli find enough
nourishment in the water here and there to multiply and produce an abundant
crop of spores.' Milks [1910] thought that his laboratory experiments indi-
cated that anthrax bacteria would grow in low, swampy places or in any place
where there was sufficient moisture. In a popular bulletin on anthrax written
by Higgins [1916] and issued by the Department of Agriculture, Ottawa,
the following statement appears : ' Our experiments would also indicate
the probability that the germ is not only capable of remaining alive in soil
but that it can also reproduce itself where conditions are favourable. All
soils, however, would not lend themselves with equal facility to the vegeta-
tion of the anthrax organism. A suitable soil must be slightly alkaline if
marked growth is to take place. We have found that a decoction of leaves
is too acid to permit the growth of the bacilli. When, however, such a de-
coction is tempered with an alkaline soil, growth might take place under
favourable temperature conditions.'
Szpilman [1914] states that the disease is indigenous in certain regions
(so-called anthrax districts) which are of a marshy humus-rich nature over an
impervious subsoil. But it is pointed out that it may also occur on other soil
formations, e.g. chalk or clay. In Pomerania, anthrax occurs almost exclu-
sively on peat pastures with lime subsoil or on heavy loam, close to river
beds [Stampa, 1935]. Pokschischewsky and Golowin [1933] note the usual
belief that favourable conditions for the development of anthrax are found
on soils that are rich in organic matter and sufficiently damp. They attempt-
ed to obtain support for this contention by periodic recording of the pH,
moisture content and temperature of the soil from permanently infected
areas, as well as by bacteriological examination of the soil for anthrax. Few
details are given and the claims of the authors are largely hypothetical. Burow
[1912] in Germany could find no correlation between anthrax outbreaks and
the composition of the soil. He considers that in the warm season the an-
thrax bacillus, thanks to nutritive substances fortuitously offered to it, finds
in the soil an opportunity for better ' development'. The surface layers in
particular have to be considered.
Writing of the disease in South Africa, Kehoe [1917] states that there
are special districts where the disease appears to have been unusually pre-
valent. The author also refers to Hutcheon, who believed that the prevalence
of anthrax in South Africa in summer and autumn was to be explained by