January 30, 1919] 



NATURE 



433 



possible by the use as solvent of "ultra-] 

 with a specific conductivity oi 0-05 — 0-07x10-" 

 reciprocal ohm. The uncertainty attached to 

 nts i 11 high dilution owing to impurities 

 in the solvent is thus practical!} eliminated, as th< 

 1 correction for 000007 and o-ooooa molar solu- 

 tions is only 0-7 per cent, and 2-5 per cent, respec- 

 tively. From their results Washburn and Weiland 

 draw the important conclusion thai the law ol mass- 

 action applies between the concentrations 0-00002 and 

 0-00007 molar, trn constant, /,-, of the dilution for- 

 mula, a. • • ' a . having the value o>oz at 18 ; 



molar k i n < 1 

 regularly up ; o a valui of 0-052 at the latter rmi- 

 ci titration. Although it is true- that the coneei 

 tion of the undiss t, i a. is very small in 



these high dilutions, yel the accuracy of the measure- 

 ments i> such that the applicability of the dilution law 

 up to 0-00007 molar ma\ bi regarded as established. 

 Arrhenius and otln-rs had previously expressed 

 the opinion that the law of mass-action is valid Ecu 

 strong electrolytes in sufficiently dilute solution, but 

 this conclusion was opei on account oi tfai 



uncertainty in the correction for the conductivity ol 

 the solvent. At the meeting considerable difference 

 of opinion was expressed on the question as to 

 whether the validity ol the mass law for strong elec- 

 trolytes in sufficiently dilute solution can be proved 

 by thermo-dynamical reasoning. 



The results just described would appear to throw- 

 some light on the cause of the deviation of strong 

 roiytes from the mass law. The fact that the 

 deviation appears in such high dilutions is difficult 

 to reconcile with any explanation based on association 

 between solvent and solute, ,-is this would introlvi 

 hydration values so great as to be in the highest degrei 

 improbable. 



Warden and others ascribe the deviation to increased 

 ionising power of the solvent owing to the presence 

 of the electrolyte, and also to the effect of the elec- 

 trolyte in increasing the ionisation of the solvent. 

 Dr.'j. W. M i' P. C. Coleman showed in a 



paper published some years ago that there is no 

 definite evidence of tli. supposi d effect of salts in 

 increasing" the ionising power of water, and they 

 show in a contribution to the present discussion, on 

 the basis of migration experinn nts, that salts do not 

 increase the ionisation of water. The latter conclusion 

 sported by the fad thai Eh< same value is ob- 

 tained for the dissociation constant of water as 

 mined bv different methods, salts being present in 

 • . but not in others. 



The consideration of the above and other su 

 explanations shows that the problem of strong elec- 

 . not yel solved, but much may be hoped 

 from the continuation of investigations, such as those 

 of Washburn, with highly purified solvents. The ques- 

 of inter-ionic forces also deserves careful study, 

 and in this connection a theoretical contribute, 

 the discussion by Dr. S. R. Milner will be read with 

 interest. 



Mr. Ghosh (Trans. Chem. Soc, tqiS) has recently- 

 put forward the view that salts are completely ionised 

 in solution, and that the apparent increase of the mole- 

 cular conductivity with dilution is due to the opera- 

 tion of electrical forces. On this basis he obtains a 

 formula which permits of the calculation, from known 

 data and a knowledge of the dielectric constant of the 

 solvent, of the ionisation of a salt at a particular dilu- 

 tion and temperature. Dr. J. R. Partington, in an 

 interesting contribution to the discussion, has critically 

 examined Mr. Ghosh's theory, and draws the conclusion 

 that his fundamental assumption, thai only electrical 

 are operative in the solution, is disproved. 



The view formerly held by many supporters of the 

 XO. 257O. VOL. I02] 



! that only the ions ol an electrolyte 



can react has now 1 1 n ibandoned, since it has been 

 shown independentl; bi Dr. Senter and In Prof. Acrei 

 that both ions and undissociated molecules an 

 • I" micaltj ai tive. sped ol the same subji 1 1 



which has received much attention in recenl years is 

 the suggestion that the catalytic activity of strong 

 acids is due parth to I i | , ,. , 1 tlj 1,, the un- 



dissociated molecule, of the acid, if it' be accepted 



that the catalytic effei t oi d aj tion, 



this is simply a special case ol thi chemical activit) 

 of non-ionised molecules and the'u ions. A plausible 

 explanation is thus afforded of the well-known fact 

 that neutral salts accelerate tin 1 1 .1 activity of 



strong acids. 



Prof. Vrrhenius consolers the latb ,1 bis 



contribution to the discussion, but favours an explana- 

 tion of the accelerating effect of foreign subs: 

 based on the assumption that these substances im 

 the osmotic pressure of the reacting substances, and 

 that the chemical reactivity of the latter is proportional 

 to their respective osmotic pressures. The available 

 experimental data do not allow this interesting sug- 

 gestion to be tested adequately. G. S. 



THE INHERITANCE OF MILK AND FAT 

 PRODUCTION IN CATTLE. 



A T the Maine Agricultural Experiment Station Mr. 

 ■**■ John W. Gowen has made a genetic study of 

 the first-generation crosses of prominent dairy breeds 

 of cattle and beef-bred Aberdeen-Angus. This work, 

 the results of which are published in the Journal of 

 Agricultural Research (vol. xv., October, 191S, 

 pp. 1-57, 6 plates), was undertaken as a link in the 

 chain of evidence necessary to the final solution of 

 the problems which are connected with the inherit- 

 ance of milk production and butter-fat production. A 

 cross-bred herd is being formed at the experiment 

 station so as to provide as much material as possible 

 for the analysis of the laws of heredity concerned 

 with the productivity referred to, and this herd has 

 now gone into its second generation. 



An indication may be given of some of the im- 

 portant results already reached by Mr. -Gowen : — ' 



(1) Black body colour is dominant to the other 

 colour in the first generation. In the second genera- 

 tion an orange-coated bull and a dark Jersey dun- 

 coated heifer were segregated out. 



(2) White marking of the body, taken as a whole, 

 appears as a dominant. Study of individual white 

 areas, however, indicates that this is due to while in 

 the inguinal region only, for this alone appears as 

 such a dominant. White spots on the face, neck, 

 shoulders, rump, flanks, and legs are generally sup- 

 pressed in the offspring when the while-spotted indi- 

 viduals are mated to solid colour. 



(3) Pigmented muzzle is dominant to one not so 

 pigmented. 



(4) A pigmented tongue is dominant to a non- 

 pigmented one — a confirmation of a previous result.' 



(5) A black switch appears to cause the suppression 

 of the other switch colours in the offspring. 



(6) Some exceptions were found to the previously 

 accepted hvpothesis of simple dominance of polled- 

 ness over the horned condition, and it is suggested 

 that a hormone secreted by the testes may have some 

 influence on the presence or absence of horns. Should 

 this prove true, it would establish an interesting 

 parallel between cattle and sheep, for in the latter a 

 sex hormone is known to affect the development of 

 the horns. 



'71 The qualities of beef production are shown to 

 bi divisibli into four general regions of the body: 



