THE AMERICAN BOTANIST. 
It'ss cactus. And this is how he explains the process. " If 
we invite Mr. Thistle, or our Mr. Cactus, into our 
gardens, and ])atiently and earnestly teach and thorough- 
(mt, it will not be very long before some member of l!is 
tril)e will see tit partly to discard some of tlie exasperating 
clothes." He further goes on to explain that "it is a 
great effort on the part of the plant to produce all these 
spines, and when all this eflort is made unnecessary, the 
plant will at once become more docile and pliable." From 
this it would ap[)ear that spines and thorns are not really 
necessary adjuncts to their lives. The homely way in 
which Burbank explains matters reminds us of the coats 
of mail used by tlie human race for purposes of protection. 
The necessity for these having passed awaj', civilized man 
now clothes himself in garments that are more suited to 
his modern civilized requirements. 
It is a fact observed by several investigators that 
plants in('.i)!;;esticati(m lose much of their spinous armour. 
There are, for instance, several varieties of roses in culti- 
vation that are absolutely thomless. Among what are 
called "hybrid perpetual" roses there are several such; 
while others present very formidable thorns. The reason 
whose ancestors were aggressively thom^-, with another 
of the same descent. ,->n'l the taint of spines comes out very 
strongly in the lor.lLing hybrid. In the case of other 
plants, such, for instance, as the acacias, the spines are 
apparently intended as aprotection against the "maraud- 
animals liave a weakness for Acacia leaves, and but for 
the spines, would be devoured out of existence. Many 
other members of the great leguminous order are spineless, 
the albizzias, for example. Being large trees, they are not 
liable to the attacks of the said "marauding animals," 
and therefore have no necessity for spines or thorns. 
Most shrubs and tree-shrubs armed with spines arc 
