LOTSV'S THEORY OF EVOLUTION- 263 



It has l)een shown 1)\- 11. R. and E. F. Armstron." that a variety of 

 substances, having the property in common that they have hut little atfinity 

 for water, are able to penetrate the walls of certain plant cells. As a 

 consequence, alterations in equilibrium are set up within the cell, and 

 changes are induced which involve alteration of the concentration and the 

 liberation of hydrolytic enzymes. The general name hormone has been 

 applied to the substances active in this manner ; it has been shown that 

 the group includes not only carbon dioxide, but materials such as hydro- 

 gen cyanide, hydrocarbons, alcohols, esters, aldehydes, mustard oils, etc., 

 all of which are normal products of plant glucosides. . . .The materials 

 so formed will be active in st:Jl further stiinulafiiiii chaiuje.'^ 



One cannot help admiring these and so many other marvel- 

 lous results which workers in biochemistry have achieved during 

 recent years, yet one cannot get awa}' from the impression that, 

 instead of getting us nearer the understanding of the basis of 

 life, they have opened our eyes to our utter ignorance of it. 

 There is not the faintest indication of any fact that helps us to 

 understand irritability. There is no indication of any explana- 

 tion of specific characters. There is nothing in them that gives 

 us a hint as to how evolution is brought about. There is 

 nothing to give us any idea how we can picture to ourselves the 

 pangenes of Darwin, De Vries, or Lotsy, and I am afraid that 

 Lotsy's theory has not brought us a step further in our search 

 for a vera causa of evolution. I thoroughly agree, however, 

 with Lotsy that species are not mere shifting phantoms, but 

 definite entities. I have on a previous occasion t pointed out 

 that while one can speak of species as constant, this does not 

 exclude that they exhibit a wide range in fluctuations or. as they 

 are usually called, variations. 



The basidiomycetes appear to me to furnish convincing proof 

 that species formation is not always due to the exclusion of 

 " genes," or, in other words, to loss-mutants. The nuclear 

 fusions known amongst them, Avhich may be equivalent to 

 sexual reproduction, take ])lace between nuclei that must in each 

 case ultimately have been derived from one and the same nucleus. 

 Provided that only previously existing " genes " are available, 

 formation of new species could, indeed, only proceed by the 

 loss of " genes." Nobody will suggest that the simple basidi- 

 omycetes have been derived from the most highly differentiated 

 ones ; on the contrary, these evidently stand at the end of the 

 series of development in this group. According to Lotsy. we 

 must then assume that the characters of these (e.g.. of Phallus) 

 were hidden in the simpler ones, but they cannot have becoine 

 apparent by the shuffling of the " genes " of the simpler ones, 

 as crossing between different species is impossible so far as our 

 experience goes. They must have been hidden in single species, 

 which, to say the least, is not likely. In many of the parasitic 

 basidiomycetes, moreover, we are well-acquainted with --o-called 

 physiological races, some of which are easily produced. Their 



* E. F. Armstrong. "' The Simple Carbohydrates and the Glucosides," 

 2nd ed. Longmans. Green & Co. Cigi2), 127. 



tRept. S.A. Assn. for Adv. of Sc, Grahamstown (1Q08), 148. 



