Discarded Hypothesis in the Drawer

The drawer marked “Pangenesis, provisional hypothesis of” holds more paper than any of my working hypotheses that lived, and I find myself this evening cataloguing it properly rather than letting it lie unsorted, because a discarded hypothesis deserves the same honest archiving as a confirmed one.

The facts of its death are these. I had supposed that every cell sheds minute gemmules into the circulation, and that these collected bodies of inheritance gather in the reproductive organs, there to be transmitted - the only device I could construct by which a character acquired through use might pass onward, and by which the reversion of long-dormant ancestral traits, those throwbacks I saw so often among my pigeons, might be explained. Francis Galton, my cousin, whose mind runs to measurement as mine runs to accumulation, proposed to test it directly. In the spring of 1871 he transfused the blood of black rabbits into the veins of white ones, and then bred the white does to white bucks. Eleven young were born. All were white. Not a single dark hair, not a grey grizzle among the litter. The gemmules, if they rode the blood, had failed to ride it.

I confess I was unwilling at first to weigh the experiment as fatal. The operation was severe, the does’ health had been compromised, one might argue the transfusion too small a dose against a lifetime’s accumulated gemmules - every excuse the reluctant mind produces when its own structure is under test. But the excuses are mine, and the eleven white rabbits are Francis’s, and the rabbits do not argue. I have since had to admit that the hypothesis fails as a mechanism, whatever service it performed in holding my thoughts together during the years of the barnacles and the fertilisation of orchids.

File it, then, under hypotheses discarded but not useless. It organized the phenomena of inheritance - reversion, prepotency, the delayed appearance of ancestral characters - into a single scheme for a decade, and a scheme that gathers facts even falsely is a stratum in which later workers may dig. Weismann has since cut the whole matter clean with his germ-plasm, and the cut is deeper than mine was. The gemmules were a scaffolding. The building did not stand. The scaffolding should still be catalogued.

To Francis I will write tomorrow: the eleven whites stand in my notes as the most instructive negative litter I have ever received, and I owe you the admission in ink that I gave you only in conversation.