May 1, 1894.] Stqjplement to the ^' Tropical Agriculturist." 
787 
acts slowly wiieii the milk is cooled down to 
about 60° ; at 55° it acts still more slowly ; 
and at 50° no action has been observed. This 
circumstance explains the fact that milk is most 
dilHcult to " keep " (i.e., it turns sour most readily) 
in warm countries and warm summer weather, 
and keeps unchanged far longer in the cool winter 
time. Other ferments besides the lactic ferment 
enter milk from the air, causing special changes. 
Milk may be preserved for any length of time 
unchanged by the use of certain chemical agents 
which are added to it — ^such are boracic acid, 
bicarbonate of soda, carbonate of soda, and sali- 
cylic acid. All these are more or less inefficient, 
and some of them are objectionable in that they 
give their own taste or smell to the milk. Sir H. 
Thomson says that 8 gr. or 10 gr. of these 
agents per pint of milk will keep it sweet for 
three or four days, twice the quantity being 
required for cream. The preservatives are perhaps 
not injurious if one pint of the milk containing 
them he drunk daily, but are likely to be hurtful 
to young children taking it. 
The best temperature for churning cream is 
56° Fahr. The butter should come in twenty 
minutes. If the temperature is above or below 
the proper point use means to bring it to the 
right degree. If too cold put boiling water into 
a long tin tube, and stir the oream until it is 
warm enough. In summer it is not possible to 
get water cold enough or ice to cool the cream 
down, but it can be put into a bag in a draughty 
place, and this will in time bring it down : or the 
churn or other vessel can be wrapped round with 
n wet bandage, and be put out where the wind 
can blow upon it ; keep ihe cloth wet. Water 
put out in dinner plates in a draughty place will 
become very cool in a short time, and this 
cold water may be put into the tin tube to stir 
the cream until it is cooled somewhat. 
Milk should be cooled quickly after it is taken 
from the cow. It will keep much longer, and 
any bad flavours in the milk will be modified. 
Cooling is now done quickly by means of refri- 
gerators. 
Lucerne should be cut some hours before being 
fed to cows. If they are allowed to graze upon 
the field tlieir milk will have a bad smell and 
taste, but if the lucerne is allowed to wilt a little 
first there will be neither smell nor taste imparted 
to the milk. 
The following recipe for cooling water for 
dairy purposes in summer time is given by Mr. 
McCormick, the expert in charge of the Tas- 
maniaii travelling dairy :— Take 8 lb. nitrate of 
ammonia and 4 lb. chloride of ammonia, both 
finely powdered : mix well together and use 5 
lb. of the mixture to every gallon of water. This 
quantity will be found suificient to reduce water 
at a temperature of 90° F. to freezing point (.'32° 
F.) in a few seconds. In order to regain the 
salts after using, evaporate the water over a slow 
tire in an iron vessel. The salts should tlien be 
laid on a plank and allowed to thoroughly dry 
in the sun. Be careful not to boil the mixture, 
because a poition of the salts will thereby be lost. 
>'ever allow the ammonia to come in contact with 
butter or cream, but stand the ve.ssel containing 
these articles in the mixture, so thai they may 
t)B entirely 6uriouud«(i by it, 
Milk tainted with " native cress," or with 
cabbage, or other plants eaten by the cow can be 
partly restored by cooling rajjidly, then heating 
to 160° F., and again rapidly cooling it. If not 
cooled and heated in this way, but put into pans 
and set for cream, the cream will rise, and with 
it the oily globules which give rise to the offen- 
sive odours and flavours, so that the skim milk 
will be nearly free, and the cream will have 
nearly all of the flavour and odour. By separat- 
ing the cream from the new milk at once the 
cream will only have its own percentage of bad 
qualities, and most of this can be driven off by 
cooling and then heating to 160° F., because the 
odours, &c., are volatile oils which are vapourised 
upon the application of sufficient heat. 
A pint of milk should weigh l-2oi lb., as near 
as can be; a gallon weighs 10 lbs. and a very 
small fraction. Dairy factories often weigh in 
10} lb. of milk for a gallon. Where the whole 
of the suppliers are shareholders this is quite 
fair. 
POONACS. 
Mr. Hooper, the Madras Government Qiiinolo- 
gist, makes the following remarks on poonac, 
which he has been examining with a view to 
their utilization as manures : — 
Castor Poonac. — This is obtained from the seeds 
of the well-known castor-oil plant. The cake 
contains from 6 to 7'5 per cent of nitrogen 
and 7 to 12 per cent of mineral matter. This 
is one of the richest poonacs. 
Ground-nut Poonac- — This is prepared from 
the .''eeds of Arachis hypogcea, which is cul- 
tivated so largely in the districts bordering ou 
the Cororaandel Coast. It contains from 5 to 7 
per cent of nitrogen, and 9 to 12 per cent of 
mineral matter. The cake from the decorticated 
seed is about one-tenth richer in albuminous 
substances than that from the undecorticated. 
Min or margom poonac is made form the seeds 
of the min tree {Melia azadirachta) and is 
characterized by its asafcetida-like smell and 
its bitter taste. The nitrogen ranges from 4 to 
5'5 per cent, and the ash is lich in phosphates. 
The cake usually retains a large quantity of 
oil, sometimes as much as 20 per cent. 
Hongay Poonac. — Hongay is the Canarese name 
for Ponyamio glabra [The Sinhalese Magul-ka- 
randa. — Ed.] The cake, which is very bitter, 
contains from 4 to 6 per cent of nitrogen-, and 4 
to 6 per cent of ash. 
Coconut Poonac is one of tiie products of the 
coconut palm on the western coast. When fresh 
it is eaten as food by the lower classes, but it 
soon decomj)oses and is fit for notiiing else than 
a manure. ' In Ceylon it is commonly used as 
cattle-food, especially for working bullocks.] It 
does jiot afford more than 'i to 4 per cent of 
nitrogen, and only a small proportion of ash. 
Mourn Poonac is prepared from the seeds of 
Ba.''.'<ia hmgif<>lia. a tree known by tlie Tamil 
name illupu ^\nd the Sinhalese >nr.— Eo,] Th* 
cake contains a large quantity of snccliarine 
matter, but is rendered nauseous on account of 
tt bitter principle being pre.>-pnt. It yields from 
i to 8 per ctnt of nitrogen, 
