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THE COW TREE. 
One of the most remarkable phenomena of the vegetable world is the cow tree, 
described by Humboldt in the following terms, as growing in the Cordilleras of 
South America : — " On the barren flank of a rock grows a tree with dry and 
leathery -like leaves ; its large woody roots can scarcely penetrate into the stony 
soil. For several months in the year not a single shower moistens its foliage. Its 
branches appear dead and dried ; yet, as soon as the trunk is pierced, there flows 
from it a sweet and nourishing milk. It is at sunrise that this vegetable fountain 
is most abundant. The natives are then to be seen hastening from all quarters, 
furnished with large bowls to receive the milk, which grows yellow and thickens at 
the surface. Some empty their bowls under the tree, while others carry home the 
juice to their children. The milk obtained by incisions made in the trunk is 
glutinous, tolerably thick, free from all acrimony, and of an agreeable and balmy 
smell. It was ofl'ered to us in the shell of the trituros, or calabash tree. We drank 
a considerable quantity of it in the evening before we went to bed, and very early 
in the morning, without experiencing the slightest injurious eff'ect. The viscosity of 
the milk alone renders it somewhat disagreeable. The negroes and free labourers drink 
it, dipping into it their maize, or cassava bread." Mr. Lockhart has subsequently 
aff'orded the following additional particulars concerning this tree : — " The Palo de 
vaca is a tree of large dimensions. The one that I procured the juice from had a 
trunk seven feet in diameter, and it was one hundred feet from the root to the first 
branch. The milk was obtained by making a spiral incision into the bark. The 
milk is used by the inhabitants wherever it is known. I drank a pint of it 
without experiencing the least inconvenience. In taste and consistence, it much 
resembles sweet cream, and possesses an agreeable smell." 
Receptacles for Milk. — All the various milky juices reside in the bark and 
leaves, and are not found in the wood. They are contained in distinct receptacles, 
and may be extracted by means of incisions chiefly in the upper parts of plants, and 
which do not extend deeper than the bark ; otherwise, they would be diluted and 
impoverished by mixing with the ascending sap. M. Berthollet has recorded a 
remarkable instance of the harmless quality of the sap in the interior of a plant, 
whose bark is filled with a milky juice of a poisonous nature. He describes the 
natives of Teneriffe as being in the habit of removing the bark from the EupJiorhia 
Canariensis, and then sucking the inner portion of the stem in order to quench 
their thirst, this part containing a considerable quantity of limpid and non-elaborated 
sap. The reservoirs which contain the milky juice of the wild lettuce [Lactuca 
virosa), are so remarkably irritable, that the slightest touch is sufficient to cause it 
to be ejected from them with considerable force. When this plant is^about to flower, 
if an insect happens to crawl over the surface of the stalk anywhere near its summit, 
a jet of milk is propelled. In general, plants which secrete these milky juices, love 
the light ; few are found to affect shady situations, and none are aquatics. By 
cultivation, their noxious properties may be greatly subdued. — Dr. Lardners 
Encyclopcediay Botany. 
