Voi,. 7, 1921 
GENETICS: J. BELLING 
197 
energy;" on the contrary, our analysis, in which the quantities ^- play 
a significant r61e, lends little support to Helm's view regarding the physical 
dimensions of economic value. Such value, or, to use more exact terms, 
"marginal utility," does not, in the analysis here presented, appear as the 
intensity factor of an energy. 
1 Papers from the Department of Biometry and Vital Statistics, School of Hygiene 
and Public Health, Johns Hopkins University, No. 40. 
2 Helm, G., Die Lehre von der Energie, Leipsic, 1887, pp. 72 et seq. 
3 Ostwald, W., Energetische Grundlagen der Kulturwissenschaften, Leipsic, 1909, p. 
155. Die Philosophie der Werte, Leipsic, 1913, pp. 260, 314-317, 326, 328. Among 
other writers who touch on the subject of the relation of economic value and price to 
energy are: Budde, Energie und Recht, Leipsic, 1902, p. 56; Winiarski, "Essay sur la 
Mecanique Sociale," Revue Philosophique, 1900, vol. 49. p. 113. See also J. Davidson, 
Qu. J. Economics, Aug., 1919, p. 717. 
4 And for others whose pains and pleasures he makes his own. 
THE BEHAVIOR OF HOMOLOGOUS CHROMOSOMES IN A 
TRIPLOID CANNA 
By John Belling 
Station for Experimental Evolution, Cold Spring Harbor 
Communicated by C. B. Davenport, June 12, 1921 
In a diploid flowering plant we may regard the chromosome group as 
consisting of a number of sets of chromosomes, two in each set. When, 
there are differences of size in the group, as has been shown in Yucca, 4 
Crepis, 6 Morus, 5 Datura, and two dozen or more other species, 8 the two- 
chromosomes of each set are of the same size; they form bivalents dis- 
tinguishable by their sizes at the first maturation divisions of the pollen- 
mother-cells; 1 and they can consequently be seen to replace one another 
in the haploid groups of chromosomes of the microspores and megaspores. 
Evidence from breeding, especially in cases of non-disjunction, also shows 
conclusively that the chromosomes of one pair are nearly equivalent or 
homologous' We may then define a diploid plant, in the strict sense, as 
one having a chromosome group formed of pairs of homologous chromo- 
somes. A triploid plant possibly comes either from the cross of a tetrap- 
loid and a diploid, or from the union of a normal germ-cell with a pollen- 
grain or egg-cell in which one of the cytoplasmic divisions of maturation 
has been omitted. (I have found one cytoplasmic division commonly 
omitted, especially after cold, in the pollen of Stizolobium, Datura,, 
etc.) The differences in size in the chromosomes of a triploid mulberry, 7,5 
and of a triploid Datura, show that the sets consist of three similar 
chromosomes each. The breeding results with plants in which one set 
consists of three chromosomes, while the other sets have only two, show 
