"The singularity of its shape is well adapted to these purposes; for, different from other newly hatched birds, its back from the scapula downwards is very broad, with a considerable depression in the middle. This depression seems formed by nature for the design of giving a more secure lodgement to the egg of the Hedge-sparrow, or its young one, when the young Cuckoo is employed in removing either of them from the nest. When it is about twelve days old, this cavity is quite filled up, and then the back assumes the shape of nestling birds in general."(Letter to Hunter at the Royal Society, as above) Jenner's nephew assisted in the study. He was born on 30 June 1737.
"the singularity of its shape is well adapted to these purposes; for different from other newly hatched birds its back from the scapula downwards is very broad with a considerable depression in the middle this depression seems formed by nature for the design of giving a more secure lodgement to the egg of the hedge-sparrow or its young one when the young cuckoo is employed in removing either of them from the nest when it is about twelve days old this cavity is quite filled up and then the back assumes the shape of nestling birds in general"(letter to hunter at the royal society as above) jenner's nephew assisted in the study he was born on 30 june 1737