GCTOBEE 12, 1900.] 



SCIENCE. 



547 



is suggested by the words of Pasteur :* 

 " Is it not necessary, and also sufficient to 

 assume that at the moment when the vege- 

 table organism originates, an asymmetric 

 force is active? * * * Do there perhaps 

 exist such asymmetric activities, subordi- 

 nated to cosmic influences in light, heat, 

 magnetism, electricity? Are they associ- 

 ated perhaps with the motion of the earth, 

 with the electric currents by which the 

 physicists explain the magnetic poles of the 

 earth ? We are to-day not in the position 

 to express even the least opinion on the 

 subject." 



Before we assume the existence of a vital 

 force or other mysterious agency, however, 

 to explain the difficulty, let us not forget 

 the confidence with which Berzelius asserted 

 the hopelessness of the problem of producing 

 organic compounds from purely inorganic 

 material. 



Speculation on the space relations of the 

 atoms has not been slow in extending itself 

 to other elements than carbon. More es- 

 pecially has nitrogen occupied the attention 

 of stereochemists. Many attempts to pre- 

 pare geometrically isomeric ammonium 

 compounds have been made, by introducing 

 the substituting groups in different orders, 

 without positive results. Within a year, 

 however, Pope and Peacheyf have suc- 

 ceeded in decomposing inactive a-benzyl- 

 phenyl-allyl-methyl-ammonium into its 

 dextro- and Isevo-rotatory constituents by 

 means of dextro-camphor sulphonic acid, 

 thereby aiibrding a proof of the existence 

 of stereoisomeric compounds of pentavalent 

 nitrogen, a discovery which, if confirmed 

 by the preparation of other similar com- 

 pounds, is of the very highest importance. 

 Still more recently, the same chemists have 

 obtained optically active compounds of te- 

 travalent sulphur and tin. J 



* Ostwald's Klassiker, No. 28, p. 31. 

 ■\Journ. Chem. Soc, 75, 1127. 

 X Journ. Chem. Soc. 77, 1072 ; Proceedings Chem. Soc. 

 16, 42, 116. 



More fruitful has been the hypothesis of 

 Hantzsch and Werner originally suggested 

 by the existence of physically isomeric 

 oximes, and now applied by them to the 

 compounds containing the group — IST = N — . 

 According to this view the triad nitrogen 

 atom may be regarded as occupying one 

 apex of a tetrahedron, the combined groups 

 occupying the others, or in other words, 

 the three valences of the nitrogen do not 

 act in the same plane. In the case where 

 the nitrogen atom is doubly united to 

 another nitrogen or a carbon atom, free ro- 

 tation is prevented, as in the case of doubly 

 united carbon atoms, and we may have 

 stereoisomers of the types 



a— C— b 



c—E 



and 



a— C— b 



isr- 



Benzaldoxime, for instance, exists in the 

 forms 



C,H,.C.H C,H,.C.H 



II and II 



HO.JST N.OH 



and diazobenzolhydroxide as 



II and II 



HO.N isr.oH 



while according to Hantzsch, the isomeric 

 nitramide and hyponitrous acid are simply 



HOIST HON 



II and II 



HOIST ISTOH 



It is quite possible that the Hantzsch- 

 Werner hypothesis may also find an appli- 

 cation in the study of the labile compounds of 

 the organism. Still more recently, Werner 

 has considered as stereo-isomeric a number 

 of metal-ammonias and their derivatives, 

 notably the platinum compounds 



Ci>Pt<KH; ^""^ NH3>^*< CI 

 platosemidiamine chloride, platosamine chloride. 



I have mentioned the latter examples as 

 illustrating the tendency to extend the 



