812 ANATOMY [HISTORY. internal carotids, and the communications which they make with the branches of the basilar artery. About the middle of the 17th century Rt. Hooke and Nehemiah Grew employed the simple microscope in the minute examination of plants and animals ; and the Dutch philosopher Leeuwenhoeck with great acuteness examined microscopically the solids and fluids of the body, recognised the presence of scales in the cuticle, and discovered the corpuscles in the blood and milk, and the spermatozoa in dpiglii. the seminal fluid. The researches of Malpighi also tended greatly to improve the knowledge of minute structure. He gave the first distinct ideas on the organisation of the lung, and the mode in which the bronchial tubes and vessels terminate in that organ. By the microscope he traced the transition of the arteries into the veins, and saw the movements of the blood corpuscles in the capillaries. He endeavoiired to unfold, by dissection and microscopic observation, the minute structure of the brain. He studied the structure of bone, he traced the formation and explained the structure of the teeth ; and his name is to this day associated with the discovery of the deeper layer of the cuticle and the Malpighian bodies in the spleen and kidney. In these difficult inquiries the observations of Malpighi are in general faithful, and he may be regarded as the founder of histological anatomy. 30, Nicolas Steno described with accuracy the lacrymal gland and passages, and rediscovered the parotid duct. Bellini studied the structure of the kidneys, and described the tongue and tonsils with some care ; and Drelincourt laboured to investigate the changes effected on the uterus by impregnation, and to elucidate the formation of the foetus. The science might have derived still greater advantages from the genius of Regnier de Graaf, who investigated with accuracy the structure of the pancreas and of the organs of generation in both sexes, had he not been cut off at the early age of thirty-two. Lastly, Wepfer, though more devoted to morbid anatomy, made, neverthe less, some just observations on the anatomical disposition of the cerebral vessels, the glandular structure of the liver, and the termination of the common duct in the duodenum. tysch. The appearance of Frederic Ruysch, who was born in 1638, and became professor of anatomy at Amsterdam in 1665, gave a new impulse to anatomical research, and tended not only to give the science greater precision, but to extend its limits in every direction. The talents of Ruysch are said to have been developed by accident. To repel the audacious and calumnious aspersions with which De Bils attacked De le Boe and Van Home, Ruysch i published his tract on the valves of the lymphatics, which completely established his character as an anatomist of originality and research. This, however, is the smallest of his services to the science. The art of injecting, which had been originally attempted by Eustachi and Varoli, and was afterwards rudely practised by Glisson, Bellini, and Willis, was at length carried to greater perfection by De Graaf and Swammerdam, the former of whom injected the spermatic vessels with mercury and variously - coloured liquors; while the latter, by employing melted wax with other ingredients, made the first approach to the refinements of modern anatomy. By improving this idea of using substances which, though solid, may be rendered fluid at the period of injecting, Ruysch carried this art to the highest perfection. By the application of this happy contrivance he was enabled to demonstrate the arrangement of minute vessels in the interior of organs which had escaped the scrutiny of previous anatomists. Scarcely a part of the human body eluded the penetration of his syringe ; and his discoveries were proportionally great. His account of the valves of the lymphatics, of the vessels of the lungs, and their minute structure ; his researches on the vascular structure of the skin, of the bones, and their epiphyses, and their mode of growth and union ; his observations on the spleen, the glans penis, the clitoris, and the womb impregnated and unimpregnated, were but a limited- part of his anatomical labours. He studied the minute structure of the brain ; he demonstrated the organisation of the choroid plexus ; he described the state of the hair when affected with Polish plait ; he proved the vascular structure of the teeth ; he injected the dura mater, the pleura, the pericardium, and peritoneum ; he unfolded the minute structure of the conglomerate glands ; he investigated thati of the synovial apparatus placed in the interior of the joints ; and he discovered several curious particulars relating to the lacteals, the lymphatics, and the lymphatic glands. Meanwhile, Meibomius rediscovered the palpebral glands, 1670. which were known to Casserius ; Swammerdam studied the action of the lungs, described the structure of tho human uterus, and made numerous valuable observations on the coeca and pancreatoid organs of fishes ; and Kerck- ringius laid the foundation of a knowledge of tho process of ossification. John Conrad Brunner, in the course of 1687. experiments on the pancreas, discovered the glands of the duodenum named after him, and Conrad Peyer described 1677-81. the solitary and agminated glands of the intestinal canal. Leonard Tassin, distinguished for original observation, 1678. rendered the anatomical history of the brain more accurate than heretofore, and gave particular accounts of the intes tinal tube, the pancreatic duct, and the hepatic ligaments. That France might not be without participation in the glory of advancing the progress of anatomical knowledge, the names of Duverney and Vieussens are commemorated with distinction. Duverney, born in 1648, and first intro- Dtivernej duced into public life in 1676 in the Royal Academy of Sciences, decorated with the honorary title of professor of anatomy to the Dauphin, and appointed in 1679 professor at the Jardin Royal, distinguished himself by the first accurate account of the organ of hearing, and by his dissections of several animals at the academy, supplied valuable materials for the anatomical details of the natural history of animals published by that learned body. He appears to have been the first who demonstrated the fact that the cerebral sinuses open into the jugular veins, and to have been aware that the former receive the veins of tho brain, and are the venous receptacles of the organ. He understood the cerebral cavities and their mode of communication ; distinguishes the posterior pillars of the vault from the pedes hippocampi ; recognises the two plates of the septum lucidum ; and, what is still more remarkable, he first indicates distinctly the decussation of the anterior pyramids of the medulla oblongata a fact afterwards verified by the researches of Mistichelli, Petit, and Santorini. He studied the ganglions attentively, and gives the first distinct account of the formation, connections, and distribution of the intercostal nerve. It is interesting to remark that his statement that the veins or sinuses of the spinal chord terminate in the vena azygos was verified by the more recent researches of Dupuytren and Breschet, which show that the vertebral veins communicate by means of the intercostal and superior lumbar veins with the azygos and demi-azygos. His account of the structure of bones, and of the progress of ossification, is valuable. He recognised the vascular structure of the spleen, and described the excretory ducts of the prostate gland, the verumontanum, and the anteprostates. One of the circumstances which at this time tended considerably to the improvement of anatomical science was the attention with which Comparative Anatomy was beginning to be cultivated. In ancient times, and at
the revival of letters the dissection of the lower animals
