XIIL] THE BIOLOGICAL SCIENCES AND MEDICINE. 331 



data for pathological reasoning. But when the Alex- 

 andrian school, with Erasistratus and Herophilus at 

 their head, turned to account the opportunities of 

 studying human structure, afforded to them by the 

 Ptolemies, the value of the large amount of accurate 

 knowledge thus obtained to the surgeon for his 

 operations, and to the physician for his diagnosis of 

 internal disorders, became obvious, and a connection 

 was established between anatomy and medicine, which 

 has ever become closer and closer. Since the revival 

 of learning, surgery, medical diagnosis, and anatomy 

 have gone hand in hand. Morgagni called his great 

 work, " De sedibus et causis morborum per anatomen 

 indagatis," and not only showed the way to search out 

 the localities and the causes of disease by anatomy, 

 but himself travelled wonderfully far upon the road. 

 Bichat, discriminating the grosser constituents of the 

 organs and parts of the body, one from another, 

 pointed out the direction which modern research 

 must take ; until, at length, histology, a science of 

 yesterday, as it seems to many of us, has carried the 

 work of Morgagni as far as the microscope can take 

 us, and has extended the realm of pathological anatomy 

 to the limits of the invisible world. 



Thanks to the intimate alliance of morphology 

 with medicine, the natural history of disease has, at 

 the present day, attained a high degree of perfection. 

 Accurate regional anatomy has rendered practicable 

 the exploration of the most hidden parts of the 

 organism, and the determination, during life, of morbid 

 changes in them ; anatomical and histological post- 



