1892.] on Micro-organisms in their Belation to Chemical Change. 531 



This glyceric acid is thus represented by chemists : — 



(CH2OH) 



C3HA or (H)-C OH) 



(COOH) 



and this should, according to Le Bel and Yan't Hoffs theory, be 

 capable of existing in two physically isomeric forms, as easily shown 



by our models. . . 



The ordinary glyceric acid known to chemists is, however, quite 

 inactive to polarised light, and must consist, therefore, of a com- 

 bination in equal molecules of a right-handed and left-handed 

 glyceric acid. Now when the B. ethaceticus is put into a suitable 

 solution of the calcium salt of this glyceric acid, it multiplies 

 abundantly and completely consumes the right-handed molecules ot 

 the salt, but leaves the left-handed molecules entirely intact, a power- 

 fully active glyceric acid being thus obtained. 



[Demonstration of the l^vorotary power of solution of new zmc 

 glycerate with projection-polariscope.] ^ 



A number of derivatives of this new active glyceric acid have 

 recently been prepared in my laboratory : — 



Derivatives of Active Gltceeic Acid. 



Formula. 



(OsH^Os)^ Ba + 



(C,H,0,\»r + 

 (C3H503)2Ca + 

 (C3H,03)2 Cd + 

 iC.n.O,), Zn + 



(03H303)2 Mg + 



aH,03 Na 



2H2O 



3H2O 



2H2O 



liHoO 



H2O" 



H,0 



C3H5O3 



C3H,03 



Am 

 K 



C3H5O3 U 



C3H5O3 Me 



C3H5O3 Et 



Specfiic Rotation. 



[a]D 

 • - 9° 



- 10 



- 12 



- 14 



- 22 

 18' 

 16 

 20 

 15 

 20 



4-8 



9-2 



13 



- 18-5 



- 20-5 



Here again then chemistry has been enriched by a number of 

 new compounds, which we owe entirely to the unaccountable caprice 

 of this micro-organism. 



Individuality of Micro-organisms, 



Although micro-organisms are thus becoming more and more 

 indispensable reagents in the chemical laboratory, essential as they 

 are for the production of many bodies, it is always necessary to bear 

 in mind that by virtue of their vitality their nature is infinitely 



