PETROLOGY: G. P. MERRILL 
37 
tissues. So far as known to the writer, it is the first example of response of 
this sort at a distance from the point of injury. 
6. I have also some evidence that leaves will proliferate locally under 
colonies of sucking insects (mealy bug, whif e fly) , also that withholding water 
from the plant for a few days will cause it to proliferate. 
7. The nature of the shock appears to lie in the sudden interruption of the 
water current which is conceived to cause cell-precipitates or plasmolysis of 
young totipotent cells which begin to grow when they have recovered from 
the shock. 
8. The prolification at times is so much like a forest that one must assume 
that the whole surface (epidermis) of immature shoots is full of cells capable 
of growing into new plants if properly shocked but that as the tissue matures 
these cells either lose their power of response, or become more perfectly 
protected. 
9. These adventive shoots, for the most part, perish quickly and cannot be 
regarded as branches, since they have no initial connection with the ordinary 
cambium, or xylem-phloem of the mother plant. They are rather to be 
classed with filial teratomas. Later, a small proportion of them establish 
connections with the conductive tissues of the mother and persist, i.e., become 
abnormally situated branches. 
10. My observations contradict those of Prillieux and confirm those of 
Verlot and of Caruel that buds may arise from the ordinary trichomes. They 
may develop either from the base or the middle of acicular hairs. Such hairs 
arise from a red tissue, the other parts of the epidermis being green. I have 
also seen them developing from the base of glandular hairs which are 
abundant on the young internodes, but they are not restricted to these pairs. 
THE PERCENTAGE NUMBER OF METEORITE FALLS AND 
FINDS CONSIDERED WITH REFERENCE TO THEIR 
VARYING BASICITY 
By George P. Merrill 
Department of Geology, United States National Museum, Washington, D. C. 
Communicated by C. G. Abbot, January 9, 1919 
Various compilations relating to time and distribution of meteorite falls 
have been made with a view of correlating them with periodic showers, but 
with, thus far, the only result of showing that there is no apparent connection 
between them.^ Viewing the subject from a geological standpoint, that is, 
from the standpoint of an earth made up by the gradual accumulation of 
meteoric materials, and considering also the apparent more basic nature of 
the earth's interior as compared with the outer portion, I have thought it 
possible some light might be thrown upon it through a consideration of the 
