SOMK ItEMAHKS AHOLT UNITS IN UKHF.DITV ■■ Miiy 



orf,'an, tlu- pulp — or its colls or groups of cells — cannot here be rcpiv- 

 sentcd in the fertilized ovum by one »unit» in the Weismiinnian sense, 

 but the tour (iiUVrenl properties: white, yellow, sweet and acid seem 

 to be imit-cluirdcters in the same sense in which primary Mendelism 

 has later used this term. Already Näoeli and in more recent time 

 Hugo de Vries have, i)erhaps more or less conscious oi the contradic- 

 tion to the Weismannian »representation of parts», regarded such dif- 

 ferent Pro])erties (»Ei'x/eleigenschaften > ) as analytical elements in the 

 hereditary nature of organisms. 



The projx'rties or rather tlie j)()ssibility of their realisation (1 

 should say: the genotypica! factors in (piestion) may be represented 

 throughout the individual; the local conditions in the different regions 

 of an organism may prevent their appearance — and in many cases a 

 special property can only be obviously manifest in specialized organs, 

 for instance the colour of the iris in the eyes, the special negro-i)igments 

 in tile surface of the body and so on. 



But here a note should be introduced. Weismann and so far I sec, 

 ex parte also de Vries have assumed that in Ontogenesis the dividing 

 cells during the whole routine of development must totally use a good 

 deal of their assumed representative elements (be it representatives of 

 parts or of properties). Hence the different parts of the mature or- 

 ganism might not have kept the same representatives: at any rate they 

 could not have a complete (active) set of these assumed elements. It 

 is easily seen, that such views indicate a fundamental (I should say 

 genotypical) difference between the several parts of an organism. Also 

 these views are mainly morphologically stamped. Morphology operates 

 Avith »descriptive differences» (I should say phenotypical differences), 

 taking such differences as the essentials. Therefore it does not much 

 matter whether we speak of unit-parts or unit-characters, both concepts 

 are equally morphological ideas — neither physiological nor chemico- 

 biological. In old times a morphological spirit governed also ex parte 

 Chemistry and, as we can easily understand. Mineralogy — this science 

 with Botany and Zoology being the main »(o-)logies» of the »Natural 

 kingdom». The characters and properties of natural objects were re- 

 garded somewhat as special entities: for instance the qualities »yellow», 

 »hard», »fusible», »combustible and so on were inherent principles, 

 elements of the nature of sulphur. 



Primary Mendelism operated in a similar way with characters, 

 Avhich in the experiments obviously behaved as units. Almost the 

 whole bulk of »Mendelian» experiences from the first enthusiastic 



