Hemoglobin and the Universe was first written in 1954.
Even the purest and most high-minded scientist finds it expedient sometimes to assault the fortress of truth with the blunt weapon of trial and error. Sometimes it works beautifully. As evidence and as a case in point, let us bring to the front of the stage the hemoglobin molecule.
The fact is that straight trial-and-error technique would have been an unbearable trial and a colossakl error. So they used other methods. There are other methods, you know.
Asimov begins by telling the story of German chemist Hans Fischer, who discovered how sidechains are attached to which positions in the porphyrin ring. He used "trial and error" by having 60 graduate students, and had them prepare protoporphyrin... only one of the synthetic protoporphyrin's matched the natural product (and since he'd assigned number 9 to that grad student group, that's why it became called Protoporphyrin IX.)
But then Asimov went on to point out that trial and error wouldn't have worked in trying to find out the exact order in which the different amino acids occur along the protein chain. "The number of different combinations tested in all tha time (300 billion years) would be about 10 to the 179th power. The chance that the right combination would have been found is 1 in 4 X 10 to the 440th power.
Even the purest and most high-minded scientist finds it expedient sometimes to assault the fortress of truth with the blunt weapon of trial and error.
There is no question but that most or all of the secrets of life lie hidden in the details of protein structure.
Since this essay was written in July, 1954, Asimov points out in an afterword, chemists have discovered many details about the hemoglobin molecule.