Mar. 1901.] BOTANICAL SOCIETY OF EDINBURGH 49 



may be seen to divide into two ; these two are identical 

 to each other, and also to the original micrococcus (con- 

 sidered at the same point of time) by whose division they 

 w'ere produced, because if placed in the same conditions 

 they give the same manifestations of life, and divide in 

 turn. If the mother micrococcus was at its moment of 

 origin from a pre-existing micrococcus composed of a certain 

 number of particular kinds of atoms or molecules, each of 

 the daughter micrococci derived from it by j&ssion is like- 

 wise formed of the same number and kind of atoms and 

 molecules ; the sum of the atoms and molecules forming 

 the two daughter micrococci will be double the sum of the 

 atoms and molecules of the mother taken at the precise 

 instant of its birth. If the micrococcus be composed of a 

 single molecule, after fission, two molecules will result, 

 equal to each other and identical to the first. The first 

 molecule has not formed another alongside itself, but has, 

 after various transformations, been doubled into two 

 daughter molecules, equal to each other and identical to the 

 first considered before these transformation changes occurred. 

 Similar observations can be made on the microsomes of the 

 cytoplasm and the karyoplasm — they are reproduced by a 

 true process of fission. Since this fission can be verified 

 de visit in the smallest living particles, its occurrence may 

 also be granted to the molecules of living substance. Such 

 fissions {dedoublements) are known to occur in dead chemical 

 compounds. The molecule of methyl-ethyl-ketoue when 

 oxidised splits into two identical molecules of acetic acid. 

 By successive action on these two of acetic acid with per- 

 chloride of phosphorus and zinc ethyl, two molecules of 

 meythl-ethyl-ketone result, i.e. two molecules similar to 

 each other and identical to the first molecule with which 

 the reaction commenced. The oxygen, perchloride of phos- 

 phorus, and zinc ethyl may be regarded as the food supplied 

 to produce this artificial life of the molecule, while the 

 other products of the reaction — oxychloride of phosphorus, 

 hydrochloric acid, and chloride of zinc may be taken 

 as the secreta of the molecule during this process of 

 assimilation. 



Starting with one molecule, we have ultimately obtained 

 two molecules of the same substance. The first one has 



TRANS. BOX. SOC. EDIN. VOL. XXII. D 



