i) 
NATURE 
[NOVEMBER 5, 1903 
animals require iron, I have seen mules licking rusty 
iron, just as thousands of people have seen horses lick- 
ing salt,’’ to which valuable testimony he quotes an 
account of quails in Florida picking at the holes in 
the steel rails. 
But to appreciate fully what a man of blood and 
iron we are concerned with, it is necessary to obtain 
some insight into his views of what his plants and 
animals do with these relatively enormous quantities 
of the metal. 
We read on p. 5, “iron is the means of fixing the 
ammonia of the air in the soil to form nitrates. In 
any case I am sure there is a fixed law by which the 
ammonia of the air is fixed in the soil to form 
nitrates... .’’ Then, on p. 21, ‘it has been proved 
over and over again that iron is fatal to all fungi, 
consequently it is unreasonable to suggest that bacteria 
would attack a perfectly healthy animal, and destroy 
the blood containing a constituent which was a poison 
to them.”’ 
And, again, on pp. 98-99, ‘‘ The distinct chemical 
difference between fungi and what we look upon as 
ordinary plants, is that the fungi contain no iron or 
nitrogen, while these constituents are essential to 
ordinary plant life. It is known that iron and 
nitrogen are fatal to fungi, therefore the more iron 
and nitrogen animal life takes up in its food the more 
likely it is to be immune to bacterial diseases.”’ 
It might not unreasonably be expected that we had 
here plumbed the depths, but the following shows that 
there are nether regions still, for on p. 42 we have 
the astounding statement, ‘It is fully recognised 
that iron and nitrogen in combination with the phos- 
phates are the means by which the plant is enabled 
to take up the carbon of the air, . . .’’ and on p. 68, 
“‘it is admitted that the proteids are fatal to patho- 
genic bacteria.’’ Even these are not the only con- 
tributions of the author to the study of bacteria, for 
he states (p. 98) “it is recognised that all classes of 
bacteria can only live on foods corresponding in 
chemical composition to themselves,’’ which pro- 
nouncement would appear to require some explanation 
in view of the previous one regarding proteids, for 
instance, and the following, quoted from p. 33 :—‘‘ it 
is admitted that pathogenic bacteria cannot live in the 
presence of proteids.”’ 
What the author’s idea of a proteid may be we have 
been unable to make out, but there is no hesitation 
needed in regard to some of his notions regarding 
immunity, of which the following is a specimen (p. 
60) :—‘‘ Another important factor in immunity is 
electricity, which is so closely connected with the 
chemistry of the animal that it is reasonable to think 
that an animal of normal chemical combination will 
be in a position to produce much more electricity than 
an animal chemically deficient.’’ 
Immunity is a fascinating but a very difficult sub- 
ject, but the author is not deterred by the latter in his 
submission to the former attribute. 
On pp. 118-119 we read, ‘‘ although Storer does 
speak of the better kinds of humus, yet it may be a 
chlorotic humus, or it may be a humus con- 
taining a maximum chlorophyll, or any variation 
between the two, which variation would be capable 
NO. 1775, VOL. 69] 
of constituting a great chemical difference.’’ Indeed, 
we should think it would! But let us read on 
(p. 120), “if you have a field rich in all the 
essential mineral constituents, in an  assimilable 
form, and a green crop be grown in this field and 
ploughed in, and then a cereal crop be grown, this 
cereal crop will be immune to rust, to say nothing 
of other parasitical diseases.’? Here it might be said 
that the author is merely claiming that high manuring 
renders a crop more immune, did not the context show 
that his ideas are by no means so simple, and if the 
continuation on p. 120 were overlooked, ‘‘ while if 
in another field, very deficient in these assimilable 
mineral constituents, a green crop was grown of a 
chlorotic nature and ploughed in, then the cereal crop 
grown would not be immune owing to the imperfect 
chemical functions performed by what I may call a 
chlorotic humus.’’ 
And this, after all the careful work that has been 
done on the cereal rusts and other parasitic diseases ! 
On p. 131 the author declares that ‘‘ parasitic fungi 
and bacteria can only flourish when the plant (or 
animal) on which they feed is deficient in chlorophyll 
or chlorophyll matter, or their products.”’ 
An interesting specimen of the author’s quality 
appears in the following naive passage on p. 148 :— 
‘* Slugs, indeed, living as they do like the fungi mainly 
upon decaying vegetable matter, are not unlike creep- 
ing fungi, and I believe it can be shown that they 
are chemically of a similar composition.’’ Again, 
p. 158:—‘‘I have now pointed out that there are 
forms of insect life that are to all intents and purposes 
simply an extension of the fungi.” 
These suggestive quotations will, we are of opinion, 
convince the reader that the present volume cannot 
be said to be of any use to a serious student of science. 
MINES AND MINERALS OF THE UNITED 
STATES. 
Mineral Resources of the United States. Calendar 
Year 1go1. Pp. 973 and index. (Washington : 
Government Printing Office, 1902.) 
Bhai is the eighteenth volume of the well-known 
series issued by the United States Geological 
Survey, and, like those which have gone before, it is 
full of valuable information concerning the mineral 
output not only of the country itself, but also of the 
world generally. The book consists of a number of 
articles written by various experts; thus the production 
of iron ore is dealt with by Mr. Birkinbine, and the 
American iron trade by Mr. Swank. Mr. G. F. Kunz 
contributes some interesting pages upon precious 
stones, whilst the coal trade is reviewed by Mr. E. W. 
Parker. The consequence is that a more useful con- 
tribution to knowledge is made by the United States 
Geological Survey than by the British Home Office in 
its annual mineral statistics. 
The introductory remarks written by Dr. David T. 
Day tell us that the total value of the minerals pro- 
duced in 1901 is reckoned at 1,086,529,521 dollars, or 
about 223 millions sterling; this is more than twice 
the value of the mineral output of the United Kingdom 
last year. It must be pointed out, however, that the 
