24 



THE LACTEALS 



that he never investigated them — he to whom Erasi- 

 stratus had given so great cause for searching out 

 the whole matter ? " Probabl v, the milk-white threads 

 had been taken for nerves by those who had seen 

 them : and those who had never seen them, but 

 believed in their existence, rested their belief on a 

 general idea that the chyle must, somehow, have 

 vessels of its own apart from the blood-vessels. 

 What Galen and Erasistratus must have seen, Asel- 

 lius and Pecquet discovered : and Harvey gives a 

 careful review of the discovery in his letters to Nardi 

 (May 1652) and to Morison (November 1653). He 

 does not accept it ; but the point is that he recog- 

 nises it as a new thing altogether. 



A year or two after he had made the discovery, 

 Asellius died ; and his work was published in 1627 

 by two Milanese physicians, and was dedicated by 

 them to the senate of the Academy of Milan, where 

 Asellius had been professor of anatomy. The full 

 title of his book is, De Lactibus sive Lacteis Venis, 

 quarto Vasortim Mesaraicorum genere 7iovo tnvento, 

 Gasparis Asellii Cre?nonensis } Anatomici Ticinensis, 

 Dissertatio. Qua sententicz anatomicce multcz vel per- 

 peram receptcz convelluntur vel partim perceptce illus- 

 trantur. He gives the following account of the 

 discovery, in the chapter entitled HistoiHa primce 

 vasorum istorum inventionis mm fide narrata. On 

 23rd July 1622, demonstrating the movement of the 

 diaphragm in a dog, he observed suddenly, 4 'as it 

 were, many threads, very thin and very white, dis- 

 persed through the whole mesentery and through 

 the intestines, with ramifications almost endless " — - 



