INTRODUCTION xix. 



these enzymes. This points to a biological antagonism between 

 sexual and asexual modes of reproduction, or, at any rate, it 

 shows the inferiority of the latter because of its frequent 

 more or less pathogenetic or symbiogenetically inferior origin, 

 which easily renders it a source of danger to biological 

 progress and calls for repressive measures in the protective 

 adaptation of the progressive types. Dr. Beard suggests, 

 indeed, that the difference of composition has to do with this 

 biological antagonism between strenuous and pathogenic 

 organisms, and that asexual forms are built up of dextro- 

 proteins, whilst the sexual are built up of Ia3vo-albumins. He 

 contends that "the micro-organisms, bacilli, etc., of disease 

 are of necessity composed of compounds which are, stereo- 

 chemically, antitheses of those making up the normal human 

 body and that when they are 'compared with the pancreatic 

 ferments, the like is true of the ferments by means of which 

 they effect their ends. Only by means of such antithetic or 

 opposite characters of compounds and of ferments produced by 

 them could such disease-inducing organisms bring about their 

 ravages. All of which is of considerable evolutionary 

 significance and emphasizes the fact that Pathology is one of 

 the most important chapters in Evolution. "We must remember 

 that its pronounced susceptibility to disease was one of 

 Darwin's reasons for stigmatising perpetual self-fertilisation 

 as "abhorred by Nature," which in reality provides a similar 

 point of view. 



It all shows that symbiogenesis involves a definite 

 evolutionary path, and pathogenesis an opposite one, whence 

 arises a determined and well-defined biological antagonism 

 between the " good " (the symbiogenetic) and the "evil " (the 

 predaceous, indolent and pathogenetic) types, which may 

 result in wholesale destruction of the latter wherever a serious 

 clash arises indeed, wherever the respectively differentiated 

 organic substances meet. 



It thus becomes possible to determine the value of every 

 substance, of every organic operation and development, and, 



