Jone 11, 1887.] 
THE GARDENERS’ 
CHRONICLE. 
775 
POTATO CULTURE. 
(Continued from p. 736.) 
SrarcH was known for many practical uses long 
before any questions were raised as to its production. 
Ages ago it was Liane eat ВМ in Egypt and 
in Crete, though the we know for 
it is the Greek amilon анто Mat. Med., ii. 
123), which passed through many changes E. 
modern usn amidon. Nor 
the er to have been impre m 
with its stiffening ae a (etary: and * starche 
for kyrcheys " was early known in England. (Cf, 
“Starched Beard,” в, Jonson, Every Man Out of 
Мз Humour, iv 
Not long ther the close uA Де last сеа, how- 
ever, W ч Lavoisier had а y taken the experi- 
ments of Rutherford, DLE Ca nd, Dalton, 
chemical formula. By 
1836 both Payen and onse ч үп һаа studied it 
Emi ыш е апа physical points of view, as it 
any plants, the Potato ee m em. 
Eoo. ы Saussure had been studying t tion 
of light on vegetation and the chemical E ond going 
on during А} ше. 
portant а of “green c 
expressed e s view that “ fi 
is the nourishment which plants 
which surrounds them. Saussure introduced into 
the SN өнү measurements of the relative 
volumes of carboni ecom 
prod ter as an index 
of carbon taken in by a plant. The method of the 
formation of starch and its function in plants soon 
received careful expe ims bun and many pro 
visional generalisations were ayen ва 
Ре view that starch is formadi in ы only when the 
nu 
n way to views — fro 
к, owing to the dem 
There are yet many questions connected with the 
elaboration of starch and the formation of starch 
ва les, most of them probably of no interest, and 
veral apparently of no importance to the Potato 
ein Still, a knowledge of how starch is 
formed appears capable of — application in 
e ways, Such q Tt nén as the 
уу 
the main po may influence 
some of the di repe in which cultivators would 
Work with regard to oliage. 
From the results i epi investigations the fol- 
y mmarised :— 
he чана ae - a — 
acid pre and 
mposed from it 5 the оону coe er ‘the 
leaves under the agency of sunlight. 
i D Ag none of the carbon enters by the roots in 
of carbonic acid, which is in solution 
Water, as was formerly supposed, and therefore it 
does not enter by the roots at all. 
3. That the e hydrogen must be obtained from the 
кое ОЁ the air or the water taken up by the 
à That starch (C, H, о О,) is formed in the leaves 
ч течи necessarily direct sunlight, though 
ui Tate of formation is proportioned to the intensity 
the light, 
- That in the va; not — is rs no formation 
which has formed is 
tg and sese from pus place of its 
n, 
6. That hesh probably, eh is not the first 
carbon compound form the carbon in a plant 
probably passes icy E мг E starch. 
7. That the starch formed in the leaves does not 
pass as such to the tubers. 
These results have not been opiate from obser- 
vations and a on the Potato itself, but 
a t is a fair зе however, 
that what takes place k other plants is similar to 
that which takes place in the Potato. There do not 
ppear to ^ 
Potato, and the processes, suc 
the ration of the tuber, have renere but little 
attent This is и, Pro tippi some w e 
a 
È 
ped yews ry summer, 
t for the cultivator to notice is, that the 
presence “of carbon depends on leaf-action. Starch 
bei a hydro 
out pee un and it isthe source of this carbon, whether 
it be the carbonie acid of the air, or the carbonic 
acid in solution in water, or both, that has been the 
subject of so much discussion. It seems now beyond 
all doubt that the source is the carbonic acid of the 
air, and that the chlorophyll- -corpuscles are the 
agents of its decomposition into carbon and oxygen. 
What exactly is their action the cult ie cannot be 
expected to know, while physiologists are themselves 
her or not the lg dcus 
being assigned 
(where some use the term corpuscule cell others use 
the term cell). 
'The vem of cy a ae of erm кечын їп 
the leaves, к rch granules tuber, in- 
volve quest ns ot poA "beds "du walls ће 
айат із чай. more femp with the 
latt od Z cannot neglect the form 
agent external to the PAM which “ causes ” 
пе formation of starch is light, the rays belonging 
n of the spectrum we spea ak of in the whole 
as e EM ae of light is psc at а ad 
se tioni rhe But leaving at present this te 
ure айсы а aside, it seems ч be ab 
er that light sufficient to form green E я 
is not pte sufficient to form starch, 
leaves se а plant may appear to the eye ges 
green if €: inference is pee they are not 
cfle all equally starch formers. Light that 
h d through а se bed vf chlorophyll uen 
taining tissue only 2m ick lost its 
“form” starch. Ade тей С. 
even supposing leaves to be fairly 
disadvantage of fall l'age pants: اس‎ E rari is, 
ing f an 
uw "- 
however, far from y 
ase, starch in the ee Hi ded ar asa 
transition epe се the hy bons pass 
wn to the tu e formation of starch 
in the — and its sion whale there up to “ sprout- 
are points that still need to be studied, 
(To be continued.) 
NOTICES OF OF BOOKS. 
NorES OF A NATURALIST IN SOUTH ove eng 
By John Ball, F.R.S., M (Lond 
Kegan, Paul, Trench & Co. 
— no greater pleasure | for the 
н на inder 
— ae ^ е e experiences and im- 
of t fortunate in this 
to follow in 
a traveller all his life, an 
ledge of how to travel the necessary qualities to 
2 his narrative entertaining, instructive, and 
induce others to imitate him in obtaining knowledge 
from actual observation. Mr. Ball is past the 
EM vigour : manhood, yet he has paper 
journey aro th America, making m 
ben 
servations on the natural history and physical 
conditions of the country, are hints, advice an 
formati he kind most usefu persons con- 
templating a similar jour T ning words 
to say concerning the contents of this boo 
me round the South America Viris. VA was 
as five 
omer d in so short onths, к not 
дагы: o deserve апу і poing T I am led to 
hope 5 this little book may e to i dien ee 
to visit a region s 
where, in the aen reri space i time, а е 
сап view so many v and impressive aspect of 
Nature; while he ы кыайда. is mainly given to 
onti 
of the many different races that inhabit it, abundant 
eae o engage his attention and excite his in- 
tere 
м: ‘Ball estimates that he travelled 18,400 miles 
y sea at a cost of a little more than £170; and, 
i without any attempt at кйш dà the additional 
expenses of about ten weeks’ stay on land did not ex- 
ceed £100. 
Beg journey was begun in March, 1882, and the 
was from Southampton to the West Indies, 
Mot at uc Barbadoes and Jamaica, thence to 
n and across the Isthmus of ama by rail 
where only a very short stoppage was made. Nearly а 
ceeded to › Payta, which, although so short a distance 
from the former place, is within the almost rainless 
р of "E Here our author found the vegetation 
scanty as above Cairo in Egypt. They next visited 
(TN tide an excursion to the higher region w: 
made, пета by rail as far as Chicla. 
of 14,400 feet was reached, and a good sample of the 
bee obtained. "This i is the subject of a contribution 
to the epee eoad rar of the Journal of the 
Linnea ich it may be gathered that 
the кен ofa Жая 8 grim in the Andean region 
proved most satisfacto 
Several ports on the rainless const were agr 
and Mr. Ball landed at Tocopilla, situated about 
south of Payta, and about 22° south of the dms : 
* Here," says the —— * I found what I had often 
tence I had almost : 
o race 
to believe—a land ror а 
vegetable Ше...... Not on re n 
thing; not even a speck of a lichen could I detect, 
though I looked A the rock thro а lens е 
more than b absence of life, I was impres y 
the appearance of the surface, which showed € token 
а water had ever flowed over it 
sect and no lizard, no living thing, with the 
Kip that on the rocks nearest the houses са 
were sev irds, which а] her 
y and which I was not able p . l was 
ld that these birds live the in 
are kept for the needs of the plac 
Most of the water required at these desolate ports 
is obtained by distillation from sea-water, but some 
and the flora 
во well represented in the Marianne North Gallery at 
ё 
