CHEMICAL HEREDITY 



Mendel showed that in the second generation 

 the hidden characteristic of the other parent 

 becomes manifest in 25 per cent of the descendants. 

 So it must have been latent in the first generation. 

 Such cases of heredity we call Discontinuous 

 Heredity, continual manifestation of characteristics 

 Continuous Heredity. 



Heredity is far from being an absolutely sharp 

 and marked conception. Phenomena of typical 

 sexual inheritance are connected by an innumer- 

 able range of intermediate stages with the pheno- 

 mena which we call typically transitory induc- 

 tions. One could even think that Inheritance 

 represents only the limit of longeval induction, 

 of which we cannot recognise the end, because the 

 duration of our time of observation is too short. 

 If we could follow up millions of generations, if we 

 could have the age of an eternal being, we might 

 find the phenomena of variation more striking 

 than the phenomena of inheritance. The best 

 materials with which it is possible to observe a 

 great number of generations in a few weeks are 

 microbes and bacteria. There is one case known 

 which illustrates the conception of inheritance 

 most instructively. The Bacillus prodigiosus is a 

 microbe which, under normal conditions, is very 

 noteworthy because of its production of a scarlet 

 colouring matter. When this bacterium is cul- 

 tivated at a temperature of 30 to 35 degrees it 

 gradually loses its colour. The interesting fact 

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