April 6, 191 6] 



NATURE 



12 



The phenomenon of osmotic flow is therefore due 

 to the residue or excess of solvent molecules on the 

 pure solvent side; the solute molecules play an in- 

 direct part only. But the solute molecules do cause a 

 strain to be placed on the membrJine, which tends to 

 rupture the latter. 



The fundamental difference betw^een osmotic pheno- 

 mena in the gaseous and solution states is that 

 whereas the active molecules (see diagram II.) have a 

 vacuum for a medium in the gaseous case, they have 

 a liquid solvent for a medium in the solution case. 

 The other differences between compressed gases and 

 concentrated solutions nearly all proceed from this 

 fundamental one. Frank Tinker. 



University of Birmingham, March 21. 



The Expansion of a Homogeneous Function in Spherical 

 Harmonics. 



In a recent paper, entitled "Notes on Spherical 

 Harmonics " (Proceedings of the Edinburgh Mathe- 

 matical Society, vol. xxxii., 19 14), Dr. John Dougall 

 wrongly claims as new the expansion which he has 

 given there for a homogeneous function of the co- 

 ordinates of a point on a sphere. This expansion 

 was first given in ipoo by Dr. G. Prasad, in the 

 Messenger of Mathematics, vol. xxx., p. 13, and 

 again, by a different method, in 1912 in the Mathe- 

 matische Annalen, vol. Ixxii., p. 436. The method of 

 Dr. Prasad in the second paper is the same as that 

 of Dr. Dougall. S. K. Banerji. 



Calcutta Mathematical Society, 



University College of Science, Calcutta, March 8. 



PREVENTIVE EUGENICSA 



T ORD SYDENHAM and his colleagues de- 

 -■— < ser\-e the thanks of the nation for their 

 prompt and faithful discharge of the difficult task 

 allotted to them, in November, 1913, of inquir- 

 ing into the prevalence of venereal diseases in 

 the United Kingdom, their effects upon the health 

 of the community, and the means by which those 

 effects can be alleviated or prevented. No one 

 can read the commissioners' report without an 

 increased conviction of the seriousness of the 

 evil that is dealt with, of its grave and far- 

 reaching effects (even on the biological plane 

 alone) upon the individual and the race. In care- 

 ful terms and with scientific precision the com- 

 missioners give the evidence for the statement 

 '^hat the effects of the diseases in question "can- 

 not be too seriously regarded," for "they result 

 in a heavy loss, not only of actual, but of poten- 

 tial population, of productive power and of 

 expenditure actually entailed." The misery 

 account cannot be estimated. 



Except in the case of the Navy and Army, 

 there are at present no means of arriving at an 

 accurate estimate of the prevalence of venereal 

 ■diseases in Britain, and many deaths due to them 

 appear to escape official recognition. Sir Wil- 

 liam Osier considers that, "of the killing diseases, 

 syphilis comes third or fourth," and the com- 

 missioners, while rightly cautious, conclude that 

 the number of persons who have been infected 



^ Royal Commission on Venereal Diseases. P'inal Report of theCommis- 



;^^oners. Presented to both Houses of Parliament by Command of His 



lajesty. Pp. 19,. (London : Wyman and Sons, Ltd., 1916.) Price is.iid. 



with this disease, acquired or congenital, cannot 

 fall below lo per cent, of the whole population 

 in the large cities, and that the percentage affected 

 with gonorrhoea must be much larger. As re- 

 gards geographical distribution, syphilis is shown 

 to be essentially a town disease. As regards 

 the social distribution of venereal diseases as a 

 whole, there is high incidence (in descending 

 order) among unskilled labourers, in those inter- 

 mediate between them and skilled labourers, and 

 in the upper and middle classes. There is rela- 

 tively low incidence among (in descending order) 

 textile workers, miners, and agricultural labourers. 

 It is regrettable that the statistics, both of total 

 prevalence and of distribution, remain somewhat 

 uncertain. It is also to be regretted that the com- 

 missioners have allowed themselves to speak 

 repeatedly of "hereditary syphilis "^ — a quite in- 

 accurate phrase. 



One of the most tragic aspects of this wide- 

 spread human scourge is the suffering inflicted 

 on the innocent. Children infected before birth 

 may l>e blinded or deafened, or terribly diseased 

 in skin and bone, in body and mind. More than 

 half of all cases of blindness among children are 

 the result of venereal diseases in their parents. 

 Of registered still-births, probably at least half 

 are due to syphilis, and it is estimated that from 

 30 to 50 per cent, of sterility among women is 

 due to gonorrhoea. The " suffering incalculable " 

 that may be inflicted on an innocent mother, taken 

 along with wrong done to the offspring and other 

 possible consequences, have led the commissioners 

 to the recommendation that the presence of com- 

 municable venereal disease should be regarded as 

 a disqualification for marriage and as a ground 

 for a declaration of nullity — without, of course, 

 affecting the legitimacy of the children. Those 

 who still think that nothing should be done to 

 make the cure of the diseases easier, because this 

 lessens the punishment of the guilty and makes 

 indulgence safer, should consider carefully the 

 section of the report which deals with the con- 

 sequences to mothers and children. We confess 

 that it overwhelms us in its awfulness. There is 

 also to be borne in mind the terribleness of the 

 nemesis involved in the occurrence in the offender 

 himself of general paralysis or locomotor ataxy, 

 it may be ten or fifteen years after the infection. 

 An even wider consideration, especially in these 

 days of wastage, is the " enormous " economic loss 

 traceable to reduced working capacity, and the 

 heavy public cost of maintaining the various kinds 

 of patients. The commissioners are convinced 

 that the cost of curative and preventive measures 

 would soon be counterbalanced by what would be 

 saved. 



We are not here concerned with the medical 

 measures by which, according to the commis- 

 sioners, the diseases can be controlled and reduced 

 within narrow limits, but w-e wish to direct atten- 

 tion to two accessory points : — (i) There is a 

 wholesome eugenic breeze in the suggestion that 

 a warning given by a physician in regard to the 

 undesirability of a marriage shall be regarded as 



NO. 2423, VOL. 97] 



