Agassiz wanted those turtle eggs when he wanted them--not a minute over three hours from the minute they were laid. Yet even that does not seem exacting, hardly more difficult than the getting of hen eggs only three hours old. Just so, provided the professor could have had his private turtle-coop in Harvard Yard; and provided he could have made his turtles lay. But turtles will not respond, like hens, to meat-scraps and the warm mash. The professor's problem was not to get from a mud turtle's nest in the back yard to the table in the laboratory; but to get from the laboratory in Cambridge to some pond when the turtles were laying, and back to the laboratory within the limited time. And this, in the days of Darius Green, might have called for nice and discriminating work--as it did.
Agassiz had been engaged for a long time upon his _Contributions_. He had brought the great work nearly to a finish. It was, indeed, finished but for one small yet very important bit of observation: he had carried the turtle egg through every stage of its development with the single exception of one--the very earliest--that stage of first cleavages, when the cell begins to segment, immediately upon its being laid. That beginning stage had brought the _Contributions_ to a halt. To get eggs that were fresh enough to show the incubation at this period had been impossible.
There were several ways that Agassiz might have proceeded: he might have got a leave of absence for the spring term, taken his laboratory to some pond inhabited by turtles, and there camped until he should catch the reptile digging out her nest. But there were difficulties in all of that--as those who are college professors and naturalists know. As this was quite out of the question, he did the easiest thing--asked Mr. Jenks of Middleboro' to get him the eggs. Mr. Jenks got them. Agassiz knew all about his getting of them; and I say the strange and irritating thing is, that Agassiz did not think it worth while to tell us about it, at least in the preface to his monumental work.
It was many years later that Mr. Jenks, then a gray-haired college professor, told me how he got those eggs to Agassiz.
'I was principal of an academy, during my younger years,' he began, 'and was busy one day with my classes, when a large man suddenly filled the door-way of the room, smiled to the four corners of the room, and called out with a big, quick voice that he was Professor Agassiz.