Decembeb 22, 1905.] 



SCIENCE. 



839 



soluble potash salts whicli are in ordinary use. 

 After these experiments were concluded the 

 attention of the writer was called by Dr. F. 

 K. Cameron to the fact that the value of 

 ground orthoclase as a fertilizer had been 

 pointed out by several investigators in the 

 past, notably by Magnus in Germany (1850), 

 Aitken in Scotland (1887) and by the Maine 

 State Experiment Station and the Colorado 

 Experiment Station (1889 and 1901) in our 

 own country. 



A paper is being prepared to be published 

 in due time which will present all the in- 

 formation so far obtained upon this subject. 

 This country is at present dependent upon 

 foreign sources of supply for all the potash 

 used annually for fertilizer by our farmers 

 and growers, and in case of foreign wars, 

 embargoes or reprisals, we should be cut off 

 from a steady source of supply. The great 

 stimulus that has been given by our growing 

 cement industry to the art and economics of 

 the milling of rocks to almost flour-fineness 

 makes it possible to-day to consider the 

 feasibility of grinding, not only some of 

 our feldspar deposits, but even our richer 

 potash-bearing feldspathic rocks, like some of 

 the granites which we possess in unlimited 

 quantities. To the proper solution of a prob- 

 lem of this kind it is necessary to enlist the 

 interest and attention of men familiar with 

 the economics of rock grinding and the hand- 

 ling and transportation of material in bulk, as 

 well as of growers and experimental agricul- 

 turists. The object of this communication is 

 to call attention to the interest and impor- 

 tance of the problem, and to open the field to 

 all who are desirous of experimenting or of 

 making actual use of ground rock for fertil- 

 izing purposes. Allerton S. Cushman. 



Office of Pitbltc Roads. 



SPECIAL ARTICLES. 

 ziegler's theory of sex determination, and 



AN alternative POINT OF VIEAV. 



In his recent pamphlet entitled ' Die Verer- 

 bungslehre in der Biologie ' Professor H. E. 

 Ziegler proposes a new theory of sex deter- 

 mination. It was said even at the time of 



Drelincourt that no less than 262 groundless 

 theories of sex had been suggested; and it 

 may be added that since that time there has 

 been no falling off of interest in the sex ques- 

 tion if the number of new theories proposed 

 is a criterion. 



Ziegler attempts to bring the question of 

 sex determination under the prevailing view 

 of specific chromosomal action. In recent 

 years cytological speculation has largely 

 rested on the assumption that the chromo- 

 somes are the sole bearers of the hereditary 

 qualities. Hence all questions of inheritance 

 have been referred to- them, and in conse- 

 quence their changes in the cell have attracted 

 extraordinary attention. Many theories of 

 heredity have been based on the shifting 

 changes in the chromosomes alone. Their 

 capacity for stains has greatly facilitated 

 their study, while the rest of the cell that 

 does not show much differentiation in stain- 

 ing capacity has been often ignored. Only in 

 the case of the egg has the cytoplasm received 

 anything like adequate treatment. The ex- 

 perimental work of Driesch, and of Wilson, 

 in particular, has shown the important role 

 that the cytoplasm plays in development. 



Ziegler's primary assumption is that the 

 chromosomes that arise from a female indi- 

 vidual have a greater tendency to produce a 

 female; and those that originate from a male 

 individual have a greater tendency to produce 

 a male. Since the child gets as many chro- 

 mosomes from the father as from the mother, 

 the parental chromosomes as such can not 

 determine the sex. But it is to be recalled 

 that amongst the parental chromosomes some 

 have come from the grandfather and some 

 from the grandmother. The relative number 

 of chromosomes from the maternal and pa- 

 ternal lines will be variable in number on the 

 current assumption that at the reduction divi- 

 sion it is merely a question of chance which 

 member of a pair of homologous chromosomes 

 goes to one pole of the spindle, and which to 

 the other. If the chromosomes of the grand- 

 father predominate in the offspring it will be 

 a male; if the grandmother chromosomes pre- 

 dominate a female develops. 



To take an example. If the somatic num- 



