Friday, July 10, 2015

the headless assassin

It had been noted by Plagge (1938) that although the implanted brain would cause pupation in Deilephila larvae from which the brain had been removed, it would not induce pupation in the posterior fragments of ligated larvae.  The significance of this was proved experimentally by Willians (1947) who repeated the experiment on the diapause pupa of Platysamia.  A chilled brain implanted in the isolated abdomen of the pupa in diapause will not induce development, whereas it will cause development of the anterior half from which the brain has been removed.  On the other hand, the isolated abdomen will develop if it is provided with a chilled brain plus prothoracic glands.  

As in Rhodnius, the actual source of the secretion in the brain is the neurosecretory cells.  But if chains of decapitated pupae are employed and a chilled brain is implanted into the first member, development is renewed in the entire series, which may be as much as 24 cm in length.  

The Physiology of Insect Metamorphosis
V. B. Wigglesworth

Wednesday, July 8, 2015

in search of lost time

"Since I am heading off into the future, I will be helped by the scuff marks left on my sandals from when I stumbled in the past.

May everything my hand touches and my eyes see and my mouth tastes be different, but the same.  That way, all those things will cease to be still and instead will explain to me why they have been with me for such a long time; they will reveal to me the miracle of reencountering emotions worn smooth by routine."

- Transcription from the Manuscript Found at Accra