SEVENTEENTH AND EIGHTEENTH CENTURIES 143 



vivisection operation on a dog which had just before had a substantial meal, 

 and thereupon found the peritoneum and intestines covered with a mass of 

 white threads; he casually cut one of them off and saw that a fluid oozed out; 

 they were thus not nerves, but vessels of a kind hitherto unknown. Influ- 

 enced, however, by the traditional Galenian idea of the liver as a blood- 

 former, Aselli assumed that these vessels, "chyle vessels," as they are now 

 called, extended from the intestines to the liver. Nevertheless, the discovery 

 aroused general interest. Aselli 's book was reprinted several times, and a 

 number of contemporary anatomists interested themselves in this new dis- 

 covery. Among them there is one who deserves special mention — Johann 

 Vesling (15 98-1 649), who, though born in Germany, became a professor at 

 Pavia and in a handbook of anatomy, printed in 1647, gave a detailed ac- 

 count of the chyle vessels (lacteals). Twenty years after Aselli's work had 

 been published, however, a young student by the name of Jean Pecquet 

 (i6iz-74) iTiade a discovery which considerably enhanced the knowledge of 

 the newly-discovered vascular system. While performing a dissection he 

 found the canal which forms the common trunk of the lacteals and the 

 lymphatics — the so-called ductus thorackus. This contradicted Aselli's and 

 his immediate successors' belief that the lacteals lead from the intestinal 

 canal to the liver. Pecquet was born in Normandy, studied at Montpellier, 

 and eventually became body-physician to the minister Fouquet, who was 

 all-powerful in the early youth of Louis XIV. When Fouquet was sentenced 

 to imprisonment for fraud, his physician had to go with him, and after that 

 he disappears from history. He is said to have had a blind confidence in the 

 power of brandy to cure all manner of diseases — an illusion which rapidly 

 brought him to ruin. It was instead in Scandinavia, hitherto unknown in 

 science, that the problem of the lymphatic duct system was finally solved, 

 and it was a strange coincidence that two scientists from different countries 

 should have quite simultaneously and independently of each other attained 

 the same result. 



Thomas Bartholin was born in Copenhagen in 161 6. His father, Caspar 

 Bartholin, was professor of anatomy and a distinguished scientist of the old 

 school. Having matriculated in his early youth and learnt all that his own 

 country could teach him, young Thomas at the age of twenty started out on 

 his travels, which lasted for nine years. First he studied for three years at 

 Leyden and there became acquainted with Harvey's discoveries, after which 

 he worked for two years in the anatomical theatre at Pavia, moved on to 

 Naples, where he was a pupil of the old Severino, then gave a dissertation 

 for his doctor's degree at Basel, and did not return to his native country 

 before a professorship was assured to him. As professor of anatomy he did 

 splendid work, which within a short time made the unknown Danish 

 university famous throughout Europe; foreign pupils flocked to him, among 



