November 17, 1898J 



NA TURE 



53 



LETTERS TO THE EDITOR. 

 The Editor does not hold himself responsible for opinions ex- 

 pi-essed by his correspondents- Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscrifts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.'^ 



The Spectrum of Krypton. 



~\, Prof. Runge, in your last issue, points out that the wave- 



[length of the bright green line of krypton is 5570'4 (Row- 



'land's scale), while that of the auroral line is about 5571. In 



he paper presented to the Royal Society by Dr. Travers and 



in self on June 3, the wave-length is given as 55677. The 



lavc-lcngth was re-measured by Mr. I5aly on June 7, and its 



.aUie was found to be 5570"o. That of the feebler green was 



5561 'S, and of D4, the yellow line, 5S70 o. These values, 



ead by means of a grating, are very close to those given by 



,'Prof. Runge. We hope to publish photographic measurements 



|i)f the other lines shortly. William Ramsay. 



Ij University College, London, November 15. 



Stereochemistry and Vitalism. 



Ali HOUGH Prof. Japp has already replied to the criticisms 

 which have appeared in Nature on his address to the Chemical 

 Section of the British Association, we should be glad, in view of 

 the interest taken in the matter, and also because we have been 

 linvestigating externally compensated and optically active com- 

 ipounds for some years past, if you could find space in which 

 ijwe may continue the discussion and bring forward a few facts 

 lin support of our views. 



Il In the first place, we will briefly summarise the main points on 

 j which there seems to be general agreement, as follows : — Com- 

 .'pounds, optically inactive by external compensation, can be pre- 

 Ipared under symmetric conditions — such compiounds, under 

 suitable and symmetric conditions may separate from solution in 

 (enantiomorphously related crystals ; under symmetric conditions 

 iicrystals of the two enantiomorphs are deposited in equal num- 

 bers, and the crystalline deposit as a whole, as well as the mother 

 liquor, if separated, are both optically inactive. 

 ' Now Prof. Japp contended that, in order to obtain an opti- 

 ically active deposit or mother liquor from such an externally 

 ! compensated compound (without the aid of some pre-existing 

 I asymmetric influence), an intelligently selective or vital force 

 must be called into action, and consequently that vitalism deter- 

 mined the existence of optically active compounds in nature ; 

 in his reply he modifies his original contention by introducing the 

 word "constantly" ; but this modification makes very little, if 

 any, diflerenceto the arguments which we adduce. His critics, 

 on the other hand, have attempted to show, with what success 

 we do not venture to express an opinion, that chance alone, or 

 other causes apart from vitalism, may have brought about the 

 present occurrence of enanliomorphous compounds in organised 

 nature. 



Having frequently had occasion to study the spontaneous crys- 

 tallisation of externally compensated substances, we had in mind 

 various observations, especially some made during recent work, 

 which led us, from the first, to doubt the validity of Prof. Japp's 

 views. Let us consider, in the first instance, the case of sodium 

 chlorate, a substance which separates from solution in enantio- 

 morphously related crystals. On allowing saturated solutions of 

 this salt to crystallise spontaneously, we found that in only two 

 experiments out of forty-.six were equal numbers of dextro-and 

 laevo-rotatory crystals deposited (Trans. Chem. Soc, 1898,606), 

 the percentage of dextro-rotatory crystals in the 46 crops varying 

 from 2414 to 7736 ; nevertheless, the weighted mean per- 

 ceiitage of dextro-rotatory crystals obtained was 50'oS + o'li. 

 It is obvious, therefore, that on crystallising this substance under 

 symmetric conditions equal numbers of dextro-and laevo-rotatory 

 crystals are finally obtained, and yet in a single deposit one or 

 other form may be present in large excess. 



C)n the publication of Prof. Japp's address, we hastened to 

 obtain further experimental evidence bearing on this point. 

 For this purpose a saturated solution of sodium chlorate was 

 allowed to evaporate spontaneously, three unselected crystals of 

 the salt of unknown rotation being introduced as nuclei ; after a 

 week's lime each of the three crystals had grown to a large size, 

 and was very well developed. One of these, weighing 47 

 grams, was removed from the solution and broken into small 



pieces which were seeded into saturated solutions of the chlorate ; 

 the latter were then placed aside to crystallise. After a week's 

 time these solutions were full of well-developed crystals, which 

 were removed and examined ; the crystals were 269 in number, 

 and were all dextro-rotatory. 



This experiment shows that an enanliomorphous system may 

 originate from a non-enantiomorphous one without the introduc- 

 tion of any intelligently directive or enanliomorphous influence, 

 and under conditions which might well arise in an inorganic 

 non-enantiomorphous universe. This being so, it is illogical 

 to assume in the present rudimentary state of our knowledge of 

 the subject that enantiomorphism of this kind could not 

 cause enantiomorphism in a system containing a substance 

 such as racemic acid or some other externally compensated 

 compound 



Now, although a solution of sodium chlorate deposits on the 

 average equal numbers of dextro-and laevo- rotatory crystals, this 

 does not preclude the possibility of olher similar compounds 

 which separate from solution in enantiomorphously related 

 crystals giving a preponderance of one or other form, owing 

 possibly to enanliomorphous influences exerted by surrounding 

 conditions, such, for example, as the earth's enantiomorphism ; 

 in fact, as we have already pointed out (/';■«;«. Chem. Soc, 1S9?, 

 611), observations in support of this view are not lacking, 

 although they require, and are now receiving, further examin- 

 ation. 



We have also shovtn(Proc. Chem. Soc, 1898, 113) that, ap- 

 parently, a close analogy exists between the behaviour of sodium 

 chlorate and of an externally compensated mixture of dextro- 

 and laevo-rotatory sodium ammonium tartrates ; this parallel we 

 are at present investigating. The first step in our examination of 

 sodium chlorate was to ascertain the ratio between the numbers 

 of dexlro- and laevo-rotatory crystals deposited from solution, 

 with the results briefly summarised above ; obviously a similar 

 step is necessary in the case of the mixed tartrates. The 

 results which have been obtained in these experiments contrast 

 remarkably with those recorded in the case of sodium chlorate, 

 and are absolutely at variance with the views expressed by 

 Prof. Japp. Ten such solutions have so far been examined, and 

 in every case a strongly dextro-rotatory deposit was obtained, 

 the mother liquor, of course, being strongly laevo-rotatory. We 

 put these experimental results forward with considerable re- 

 servation as the work is not complete and we may di.scover 

 some disturbing influence ; but, inasmuch as attention has of 

 late been concentrated on this fascinating subject by Prof. Japp's 

 equally fascinating presentment of it, we feel compelled to make 

 this short statement of the results up to the present obtained in 

 developing the work which we have in hand. 



Much more might be written with a view to suggesting the 

 possible sequence of events which might have led to the present 

 conditions of organised nature, but it is of little use attempting 

 such a task until a great deal more experimental evidence is 

 before us. F. Stanley Kipping. 



William J. Pope. 



The following seems to me a perfectly possible, although 

 purely hypothetical, way in which any amount of an optically 

 active compound could be formed by chance chemical pro- 

 cesses. 



Let an admixture of chemical compounds be such that only 

 one molecule of an optically active compound is formed. Or, 

 if you like, let a volcanic explosion scatter a collection of equal 

 quantities of dextro and laevo molecules in such a way that one 

 molecule only falls in a certain pool of water containing inactive 

 bodies in solution. 



This single molecule must be either dextro or laevo. Let us 

 suppose it is a dextro molecule. 



Furthermore, let it be of such a nature that it can react cata- 

 lytically with surrounding molecules in such a way as to produce 

 in these an asymmetric atom : 



'■•^■ 



Cr/j Cdjl 



(1) II -I- RH., = 1 ■ . 

 Cab CabKH 



Cd.M Cd..U 



(2) I ' + IL, = I ■ -I- RH , 

 CablUl CabH 



NO. I 5 16, VOL. 59] 



