No. 543] 



NOTES AND LITERATURE 



166 



shown to be sex limited in inheritance in such a manner that it 

 seems certain they are in some way connected either with the 

 sex-determining chromatic element or with the synaptic mate 

 of this element (in the heterozygous sex). This links these 

 characters with the chromosomes, and further strengthens the 

 chromosome theory of Mendelian inheritance. 



The writer is fully aware of the danger, in dealing with sta- 

 tistical data, of drawing conclusions from insufficient data or 

 from data that have not been submitted to a full mathematical 

 analysis, such as the determination of means, norms, standard 

 deviations, and coefficients of correlation. Although I have no 

 very full or accurate data on the subject and have not actually 

 determined statistically the coefficients of correlation between 

 the characters about to be mentioned, I am of opinion, after 

 more or less superficial observation extending now over nearly 

 half a century, that there is a noticeable degree of correlation 

 between positiveness of statement, and inaccuracy of statement. 

 An illustration of this correlation will be found in a paper by Dr. 

 J. Arthur Harris, published in the November (1911) number of 

 this journal. It is now fairly well established that the norms 

 of a group of related genotypes can, in some cases at least, be 

 arranged in a frequency curve. In my review of de Vries's 

 "The Mutation Theory" 12 I cite this fact to show that the type 

 of variation represented In/ these g< not y pes comes under the head 

 of what de Vrics there defines as ''continuous variation," as 

 opposed to the "discontinuous variation," in which the norms of 

 the variants can not be thus arranged. In Dr. Harris's paper he 

 represents me as having cited the fact that these genotype norms 

 form a frequency curve as a proof of the genotype hypothesis. 

 I have not been able to find the time to look up other similar 

 citations in this paper to see whether the same inaccuracy applies 

 to them. The type of correlation we are considering is further 

 illustrated in this pap^er in Dr. Harris's definition of genotype, 

 from which he omits the word "homozygous." The definition 

 is further inaccurate in including clonal varieties under the 

 definition of genotype. The author of the term genotype, in a 

 recent lecture in this city, defined it as "the descendants of a 

 single homozygous individual propagated by self-fertilization." 13 



"Amer. Nat., Dec., 1910. ' 

 that the word genotype should be replaced, in the above sense, % by "biotype" 



