A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 
“To the solid ground 
Of Nature trusts the mind which builds for aye.’-—WoRDSWORTH. 
THURSDAY, NOVEMBER 5, 
1903. 
BLOOD AND IRON. 
Plant Disease and its Relation to Animal Life. By 
E. F. Wright. Pp. vi+ 160. (London: Swan 
Sonnenschein and Co., Ltd., 1903.) Price 3s. 6d. 
HIS little book with so alluring a title is 
emphatically disappointing, and would appear 
to have been written by a compiler quite inadequately 
informed on the subject, especially in its botanical 
aspect. 
The principal contention of the author seems to be 
that, because iron is necessary for the production of 
chlorophyll in the green plant, and is an indispensable 
ingredient in relation to the haemoglobin of the blood 
in animals, these two bodies, chlorophyll and hamo- 
globin, are the same. Thus on p. 1 we read, ‘‘ Now 
what chlorophyll is to the plant, hazmoglobin is to the 
animal, the one being a red modification of the other,” 
and, p. 69, ‘‘ As hemoglobin is allied to the proteids 
and a red modification of chlorophyll, it follows that 
the hemoglobin of the animal varies as the chlorophyll 
or chlorophyll products vary in the plants eaten.”’ 
He then proceeds to argue that if an animal eats 
plants deficient in chlorophyll (i.e. chlorotic) it suffers 
the evils due to want of iron—e.g. (on p. 6) ‘‘ animals 
eating chlorotic food must be deficient in sugar, fats 
and proteids,’? which would seem to indicate (since 
the author appears not to discriminate between 
chlorosis and etiolation) that people who are fond of 
cauliflowers, asparagus, endive, rhubarb, and the like, 
run risks hitherto unsuspected. For note this (p. 13), 
“if my contention is correct, the susceptibility to 
certain bacterial diseases is directly traceable to the 
use of chlorotic food.’’? And on p. 15, ‘‘ from which 
it follows that a chlorotic plant will contain less pro- 
teids than a plant containing the maximum quantity 
of iron.’”? And, again, p. 28, ‘‘it is clear that there 
must be a large number of animals living entirely or 
partly on this chlorotic vegetable food, from which it | 
follows that a large portion of animal life must be 
NO. 1775, VOL. 69] 
| 
| more or less anemic through eating this chlorotic 
food.”’ 
We have already stated that the author draws no 
distinctions between different forms of chlorosis and 
etiolation, and puts the former down simply to a lack 
of iron. Now let us see what he regards as the 
measure of this deficiency, bearing in mind that 
modern plant physiology teaches us that the traces of 
iron found necessary to develop the peculiar form of 
chlorosis in question are:so minute that it is often 
somewhat difficult to ensure the absence of that 
element in experimental cultures. 
On p. 7 we read, ‘‘ Yet there are many soils quite 
wanting in iron, and in the history of agriculture you 
never read of manuring with iron, excepting possibly 
in the case of some experimental plots, although some 
iron has been used of late years in the form of basic 
slag, which contains about 18 per cent. of iron,”’ and, 
further on the same page, ‘‘ Unfortunately, much 
vegetation is deficient in iron, and consequently 
chlorotic, and it would seem simpler instead of wash- 
ing with sulphate of iron, as is now occasionally done, 
to have recourse to manuring the ground with iron,”’ 
all of which goes to show that the author’s notions 
as to the relations between iron and plants are, to say 
the least of it, crude. Does he seriously suppose that 
basic slag is used as manure on account of the iron 
it contains ? 
But lest there should be any risk of misunderstand- 
ing the author’s meaning here, we may quote the 
following from this amusing book. After describing 
how one lamb of a flock, too weak to proceed, was 
rescued and brought up by the children of a black- 
smith, the author continues (p. 34), ‘‘ This lamb: 
grew up by grazing on the grass growing round this 
{the blacksmith’s] shop, and was shorn three times in 
three years,’’ &c., and he explains the excellent con- 
dition of this lamb as follows :—‘‘ In the first place, 
it is quite certain there would be plenty of iron in the 
soil for some distance round a country blacksmith’s 
shop, owing to rusty iron being carried about, to say 
nothing of the scales of iron and iron filings,’’ &c. 
To show what gourmands for iron the author’s 
‘animals are, we quote from p. 93 :—‘‘ And to show that 
B 
