THE DETERMINATION OF SEX 



Botanist of Lemburg Professes to Have Found That Age of Pollen at the Time of 

 Fertilization is Determining Factor — Claims High Percentages in Experi- 

 ments — Has Tested Discovery in Animals and Man, He Says. 



P. J. Wester, 

 Horticnltnrist in Charge oj Lamao Experiment Station, Philippine Bureau of 



Agriculture. 



first in Latin and later translated into 

 English, in which form it appeared in 

 International Clinics, Vol. 3, 22nd 

 series, 1912, prefaced by a review by 

 Dr. S. W. Carruthers, of Norwood, 

 England, Ciesielski thus relates the 

 circumstances under which the dis- 

 covery of the law of sex determination 

 was made : 



"As soon, then (1876), as the sex of 

 the plants Cannabis sativa . . . 

 could be determined I took out all male 

 plants from the . . . garden, leav- 

 ing only female ones, . . . There- 

 after, as soon as the female plants were 

 mature I fertilized them with pollen 

 from the male plants . . . simply 

 by shaking the male plants over them. 

 The female plants in the upper garden 

 I fertilizea daily at sunrise, but those 

 in the lower garden just before sunset. 



HIGH PERCENTAGE SECURED. 



"The seed collected from those divi- 

 sions 1 sowed again in 1877, separately 

 in the upper and lower portions of the 

 garden, but in new plots, to avoid 

 any possible fallacy from seeds of the 

 former experiment casually and spon- 

 taneously shed in the old plots. The 

 result was that from seed derived from 

 plants fertilized at sunrise I obtained 

 85.5% of male plants, while the seeds 



'For the benefit of readers who are not in touch with recent biological researches, it should 

 be said that many of the investigators who have given the most study to the question believe 

 the determination of sex depends on the inheritance of a Mendelian factor differentiatmg the 

 sexes. Microscopical studies of the cell indicate that the presence of an accessory or "x" chromo- 

 some in the sperm or egg (usually the latter) is the deciding factor, in some species. If sex does 

 Mendelize, the proportion of males and females is thus subject to the laws of chance — in other 

 words, an equal number of each will be produced, if the quantities involved are large enough to 

 furnish accurate statistical results, and if diflferential mortahty does not take place. — The 

 Editor. 



207 



THE determination of sex is a 

 riddle that for ages has puzzled 

 the minds of men and numerous 

 are the theories that have been 

 advanced in an attempt to explain 

 which factors determine the sex in the 

 progeny — theories advanced only to be 

 abandoned as untenable in the light of 

 further experimentation. It has long 

 seemed and by many been asserted 

 that sex determination was a mystery 

 held in trust by Nature that was forever 

 to remain unravelled'-. It now appears 

 that while it has continued to occupy 

 the minds of many scientists, the prob- 

 lem may in reality have been solved for 

 some years. Tliis remarkable discovery, 

 which unquestionably will mark a new 

 epoch in animal breeding no less than 

 in the eugenics of the human race, if 

 the apparently simple law involved is 

 upheld by thorough tests and becomes 

 generally diffused, was made in 1878 

 by Prof. Theophilus Ciesielski in Lem- 

 burg as a result of continued experimen- 

 tation begun in 1871. 



The earliest investigation by Ciesi- 

 elski was conducted on Indian hemp 

 {Cannabis sativa) and garden spinach 

 {Spinacia oleracea.) It is not here 

 necessary to go into detail regarding 

 the earlier years of experimentation 

 which yielded negative results to the 

 investigator. In a paper published 



