248 
REVIEW OF LEIBIG. 
There is great economy in keeping hens where 
there are suitable conveniences for them; for if 
furnished with plenty of proper food and a warm 
room, even in winter they will produce two or 
three times the value of their food in eggs, as they 
command a larger price at that time. At all oth¬ 
er seasons when they run about, they select for 
themselves nearly all the food they consume, 
which would otherwise be of no use to their own¬ 
er ; nay, frequently its consumption is of positive 
benefit to him. Such are all insects, grubs, worms, 
and their larvae, and any animal or vegetable food 
scattered around the premises, that would other¬ 
wise .become putrid, and taint the atmosphere. 
If to the usual qualities of hens, a breed of pe¬ 
culiar elegance, of graceful forms, and beautiful 
plumage, be added, together with entire adapta¬ 
tion to the economical purpose required, good lay¬ 
ers and good carcase, we have a combination of 
utility, luxury, and taste in this bird, which should 
commend them as general favorites. 
I will add a fact, which is not known, except, 
perhaps, to some of peculiarly discriminating and 
highly-cultivated palates, that in addition to their 
stronger claims on the score of beauty, the flesh 
of the yellow-legged is much richer, and more 
highly flavored, than either the white or the black¬ 
legged hens. 
E. L. Allen. 
Translated for the Gardeners' Chronicle, 
from the German of Dr. Hugo MM. 
REVIEW OF LEIBIG. 
(Continued from Page 253.) 
It is, therefore, clear (continues Dr. M.,) that 
Leibig has completely failed to prove that plants do 
not use humus for their food. Besides, the ques¬ 
tion whether plants feed on organic or inorganic 
substances, was mooted long before the publication 
of Leibig’s work. Although it is certain that the 
chief portion of plants is formed by the assimila¬ 
tion of inorganic substances, yet, the collateral 
questions, whether they receive organic as well as 
inorganic matter; whether all or only some plants 
require organic substances for their existence— 
these questions are far from an ultimate and scien¬ 
tifically-corroborated solution. Conclusions, more¬ 
over, merely based on uncertain observations, or 
made merely at random, can not be of value, and 
ought to have been replaced by minute and well- 
devised experiments. In this manner, Leibig 
might have become eminently useful to science. 
He professes (it is true) to despise minute experi¬ 
ments; nevertheless, the Appendix to his Work 
contains the reprint of some made by Hartig, 
which he adduced in corroboration of his doctrine. 
But it is unworthy of a great chemist (concludes 
Dr. M.) to mix up experiments of men like Davy 
or Saussure, with those of a gentleman like Hartig, 
who, we are sure, does not aim at the distinction 
to be considered a chemist—a science foreign to 
his pursuits. 
The experiments which have been hitherto 
made relating to the question of the organic or in¬ 
organic nourishment of plants, may be divided into 
three Classes. 1. Plants were reared in soil des¬ 
titute of humus, either with distilled water or such 
as contained carbonic acid. Under both these cir¬ 
cumstances they do not prosper; still, this does 
not prove the necessity of organic food, because 
they are here equally deprived of other inorganic 
substances, which they are in contact with, under 
common circumstances. 2. Or, plants have been 
reared in powdered charcoal. Leibig says, (p. 58,) 
that they will attain in this material the most lux¬ 
uriant growth, flower, and bear fruit; but he 
merely quotes in evidence the experiments of Lu¬ 
cas, reprinted in his Appendix. But the reasoning 
of Leibig, under this head, is illusory. Lucas 
speaks of vigorous vegetation of plants reared in a 
mixture of charcoal, powder, and decayed leaves ; 
of such as are grown in charcoal powder alone, he 
merely says that they speedily become rooted. 
Of their further vegetation he says nothing; and 
it has been proved by the experiments of Zuccarini 
that plants will not grow at all, or very badly, in 
this substratum. The same is stated by Saussure 
(Bibl. univ. xxxvi., p. 352,) who relates, that peas 
reared in charcoal did not grow much better than 
those planted in mere sand. The third class of 
experiments relates to the question, whether plants 
will absorb organic substances dissolved in water, 
and especially humates; and whether they will 
prosper under these circumstances. The experi¬ 
ments of Saussure, Davy, and Sprengle, are affirm¬ 
ative ; but Leibig has reprinted (as stated before) 
those of Hartig, which are negative. The whole 
question, therefore, is, to say the most of it, one 
et undecided. At any rate, it can not be solved 
y experiments upon a single species of plants; 
and it is begging the question to state (p. 122) 
that, “ All plants are the same in the chemical 
nature of their nutritive process.” 
Dr. Mohl then proceeds, at some length, to re¬ 
fute this unqualified assertion of Leibig. There 
is a considerable number, he says, of true parasites, 
which require for their food the juices of living 
plants. It can not be doubted that such plants re¬ 
quire substances of a peculiar chemical combina¬ 
tion and quality for their food. Many such para¬ 
sites are not green, and therefore can not decom¬ 
pose carbonic acid, so that their food must neces¬ 
sarily consist of substances already assimilated by 
other plants, and stand in the same relation to the 
mother plant as the flower and fruit of other vege¬ 
tables to their respective branches. Now this sort 
of nutrition from substances derived from living 
plants is also proper to a very large number of 
parasites (Loranthacse) which are quite green, and 
therefore provided with organs for decomposing 
carbonic acid. Such plants are entirely similar in 
structure to those which grow in soil; but they 
must, of necessity, possess the capacity of feeding 
on substances already assimilated by other plants. 
To these true parasites are to be added the spuri¬ 
ous parasites, which feed on decaying organic 
matter, among which some have green leaves, 
and others are destitute of that color. The latter 
can have no capacity for decomposing carbonic 
acid, forming organic matter from it and water. 
The same is also the case with many other plants 
of a green color, which, although they decompose 
