day sent me a crystalline body which he had obtained by the
action of peroxide of lead upon this acid; I immediately thereupon
wrote to him with great joy, and without having analyzed
the body, that it was allantoin. Seven years before I had had
this body in my hands; it had been sent to me by C. Gmelin for
investigation, and I had published an analysis of it in Poggendorf's
Annalen; since that time I had not seen it again. But
when we had analyzed the substance obtained from uric acid
there appeared a difference in the amount of carbon, the new
body gave one and a half per cent carbon less, and since the
nitrogen had been determined by the qualitative method a
corresponding quantity (four per cent) of nitrogen more; consequently
it could not possibly be allantoin. However, I trusted my
eye-memory more than my analysis, and was quite sure that it was
allantoin, and the thing now to be done was to find the remains of
the substance previously analyzed in order to analyze it afresh.
I could describe the little glass in which it was with such
precision that my assistant at last succeeded in picking it out from
among a couple of thousand other preparations. It looked exactly
like our new body, except that examination under the lens showed
that Gmelin, in the preparation of his allantoin, had purified it
with animal charcoal, some of which having passed through the
paper in the filtration had become mixed with the crystals.
Without the complete conviction which I had that the two bodies were identical, the allantoin produced artificially from uric acid would undoubtedly have been regarded as a new body, and would have been designated by a new name, and one of the most interesting relations of uric acid to one of the constituents of the urine of the foetus of the cow would perhaps have remained for a long time unobserved. In this manner it came to pass that everything I saw remained intentionally or unintentionally fixed in my memory with equal photographic fidelity. At a neighboring soap-boiler's I saw the process of boiling soap, and learned what “curd soap” and “fitting” are, and how white soap is made; and I had no little pleasure when I succeeded in showing a piece of soap of my own making, perfumed with oil of turpentine. In the workshop of the tanner and dyer, the smith and brass-founder, I was at home, and ready to do any hand's turn.
In the market at Darmstadt I watched how a peripatetic dealer in odds and ends made fulminating silver for his pea-crackers. I observed the red vapors which were formed when he dissolved his silver, and that he added to it nitric acid, and then a liquid which smelt of brandy, and with which he cleaned dirty coat-collars for the people. With this bent of mind it is easy to understand that my position at school was very deplorable; I had no ear-memory and retained nothing or very little of what is learned through this
