We have reason to believe that the chromosomes of the father plant and mother plant, side by side, represent blocks of parental characters.
William Bateson (1902)
The Mendelian factors, today known as genes, were abstract entities, inferred entirely from the results of breeding experiments. Initially there was nothing to tie them to any particular structure within cells. Bateson was among the first to see a link with chromosomes and he and Saunders cited Guyer in this context (Chapter 8). However, as evidence for a chromosomal location became stronger Bateson's doubts increased. It was not a question of Bateson not seeing the wood from the trees. His idea of what constituted the wood differed from that of others. They saw a collection of genes. He saw genes plus something else that was somehow related to the question of the origin of species. What was the something else and where was it located? Was it on the chromosomes like the Mendelian factors? Or was it elsewhere, perhaps outside...