174 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



nor do they appear to have seriously respected the wishes 

 of the King to return the specimen sufficiently intact for 

 exhibition in the Museum. The origin and course of 

 the cystic and hepatic ducts are worked out, the 

 epididymes are unravelled, and their factors disclosed by 

 the injection of a coloured fluid. The bladder is astutely 

 recognised as comparable to the allantois of higher 

 animals, and the urogenital organs receive masterly 

 treatment. Even the comparative anatomy of the lung 

 is only partially baffling, as we gather from their happy 

 comparison of the chambered lung of the Tortoise with 

 the almost parenchymatous lung of the Mammal. Vivi- 

 section itself is resorted to in matters of difficulty, and 

 they were among the first to investigate the physiology 

 of the lungs in a living animal in which respiration was 

 maintained with a pair of bellows. The same experiment 

 had been successfully demonstrated to the Royal Society 

 by Robert Hooke four years before, but they go further 

 than Hooke, and find that in the inflated lung an injec- 

 tion thrown into the pulmonary artery passes more readily 

 through the capillaries into the pulmonary vein than in 

 the deflated organ. To close the list of their successes, 

 they discuss the nictitating membrane of the eye and 

 its muscles, the relations of the tympanic cavity and the 

 columella, and they realise that the extrusion of the head 

 and the neck of the Tortoise is just as much a question of 

 muscular contraction as its withdrawal — a simple deduc- 

 tion, but one which later biologists have not always com- 

 prehended. On the other hand, in spite of several 

 ingenious — but misleading — experiments, they fail to 

 grasp the broader facts of the Reptilian circulation. They 

 confuse the hepatic veins with the postcaval, the 

 aortic arches are regarded as branches of a single vessel, 

 and, worst of all, they deny that the lungs exercise any 



