3) Prune leaves and probe to the growing cone without damage to tissue. 4) Pack a small wad of cotton into the terminal point. 5) Soak this cotton by dropping .2% aqueous solution of colchicine on same. 6) Add glycerine to cotton to improve penetration of colchicine. 7) Place drop of colchicine on cotton morning and evening for four days. 8) Remove cotton wading from bud on 5th day. 9) If sufficient tests at hand, allow cotton to remain on some buds. 10) Try for at least one hundred buds treated. 11) Observe growth during first season and also next season. 12) If treated bud dies, watch for growth among lower laterals. 13) Evidence of changes appears in the new leaves, darker, thicker, greener. 14) Conclusive evidence of doubling rests with microscopic and anatomical analysis which is a task for trained technicians only. The above procedures are suggestions for a start and everyone will wish to make changes suited to his particular needs. The concentration of colchicine need not be exact as in an analytical experiment in chemistry. One gram dissolved in 500 ml. water is an adequate and a sufficiently careful measurement. The local pharmacist or physician is well acquainted with colchicine in the practise of medicine since this drug is a standard for gout. Effective use may be made from two specific areas of plant breeding. First, doubling of chromosomes changes sterile hybrids into fertile individuals. This is a promising field and whenever such hybrids are discovered, efforts should be made to apply the colchicine technique. Second, doubling of the chromosome number makes possible hybridization of individuals heretofore unsuccessful in such effort. In both instances germ plasm of wide genetic difference is incorporated into a new propagating breeding stock. In the case of the sterile hybrid transformed into fertile individuals, no counting of chromosomes is necessary because restoration of fertility is evidence of changes in the chromosomal makeup. However, the second type of experiment requires microscopic analysis. There are a number of fundamental research problems in the plant sciences associated with the treatment of plants with colchicine. From horticultural subjects such as the apple,(3) pear, cranberries,(4) and grapes, it is obvious that periclinal chimeras will be of prime importance in analysis of results in treatment of nut trees. Following the treatment of a growing point with colchicine the outer layer of cells may be doubled by colchicine but the lower layers may remain unchanged. Or a reverse of this situation may obtain, and even other types. Since the formation of pollen takes place from a certain layer it is very important that such specific layers are changed. The course of plant breeding can be altered by these kinds of changes. To our knowledge, no investigations of periclinal chimeras have been made with nuts, following treatment with colchicine.