@he Scientific Guonirer. 
DECEMBER, 1888. 
Vegetable Cows. 
EVERAL natural orders of the vegetable kingdom include 
plants that are characterised by the secretion of a fluid 
closely resembling milk in appearance and consistency, 
and a familiar example of these is to be seen in our 
common milkweed (Asclepias cornutt), which is well 
known to everybody. In some plants, this milky fluid 
is of the most venomous nature; in others, it possesses active 
medicinal virtues; in others, it yields a product (such as India 
rubber and gutta percha) of the highest importance to the arts 
and industries ; and, in others still, it proves of value as a human 
aliment. Since the same general properties characterise the 
plants of each natural family, it seems an anomaly that, in the 
same order, we should find the species of one genus producing a 
lactescent fluid of a highly poisonous nature, and those of another 
yielding one that is entirely innocuous. Yet such is often the 
case, and we have a striking example of it in the bread fruit order, 
the Artocarpace, which, on the one hand, includes the celebrated 
upas tree of Java, which, when pierced, exudes a milky juice con- 
taining an acrid virulent poison (antiarin), the smallest quantity of 
which will kill the largest animal, and, on the other, the famous 
Brosimum utili of South America, which yields a copious supply 
of rich, wholesome milk, of as good a quality as that from the 
cow. ‘There are several other instances in the vegetable kingdom 
of such an association, in the same natural order, of plants that 
produce noxious lactescent juice with others which yield a whole- 
some one adapted for man’s use, and which may therefore be 
designated as “vegetable cows.” ‘To speak only of the latter 
class, the most remarkable example is the species of Brosimum 
just mentioned, which was discovered and made known by the 
*From the Sczentefic American. 
VoL, III. 12 
