DEMONSTRATIONS 1. Experiments upon the glands of internal secretion in R a n a and Bufo larvae. BENNETM. ALLEN, University of Kansas. 2. Positional changes in the visual cells and retinal pigment to graded intensities of light. L. B. AREY, Northwestern University Medical School. 3. Models illustrating the development of the hypophysis cerebri of the frog. WAYNEJ. ATWELL,Department of Anatomy, Medical School of the University of Michigan. 4. 'X-ray plates illustrating anatomy in the living. C . R. BARDEEN, University of Wisconsin. 5. Models and corrosion preparations showing the branching of the hepatic ducts in human embryos and newborn. E. A. BAUMGARTNER, Department of Anatomy, Washington University Medical School. The hepatic anlage in a 4.2 mm. human embryo is round, extending cranially and ventrally from its wide connection with the gut. .Hepatic trabeculae grow from its lateral and ventral surfaces. A short caudal portion bears no traveculae and is probably the pars cystica. A single ventral pancreatic anlage projects from the right side of the caudal end of the hepatic outgrowth caudal to the pars cystica. In a 7.5 mm. specimen the hepatic duct divides near its origin into a small right ductule and a very much enlarged plate-like duct from which hepatic trabeculae are given off in all directions. The gall bladder is attached to the common duct by a short cystic duct. A model of a 17 mm. embryo shows the distal end of the gall bladder directed cranialward. The hepatic duct and its right subdivision are lengthened. Hepatic trabeculae arise from the right and left ducts. Another specimen of the same size shows several small hepatic ducts arising from the cystic duct, one of which anastomoses with a radicle arising from the hepatic duct. This specimen also shows an enlarged distal end of the hepatic duct, similar to that in younger stages. Models of 25 mm. and 41 mm. embryos show growth in length of cystic and. hepatic ducts. In the 41 mm. specimen the hepatic duct breaks up into several laterally-projecting ducts from which many hepatic trabeculae are given off. Corrosion preparations of the hepatic tree in several new borns have been made. These show as a rule a right and a left hepatic duct with smaller and larger subdivisions spreading into the liver. 53 54 AMERICAN ASSOCIATION OF ANATOMISTS 6 . Microscopical preparations of a closely graded series of hind limbs of pigs showing the early stages in the development of the f e m u r and the thigh musculature. EBEN J. CAREY, Department of Anatomy, Creighton University. 7 . Preparations illustrating the origin of the corpus luteum of the sow. GEORGEW. CORNER,Anatomical Laboratory, University of California. 8. Stages in the development of brachydactylism in the fowl. C. H. DANFORTH, Department of Anatomy, Washington University Medical School. Feet of brachydactyl chick embryos fixed on about the tenth day of incubation and stained in toto by the Van Wijhe method show various degrees of diminution in the cartilaginous skeleton of digits IV. The preparations are thought to indicate that the reduction in the number of phalangeal cartilages is due to a fusion of the anlagen of these elements. The skeletal elements of the feet of a few adult birds are shown for comparison. 9. Material illustrating the early reactions of blood and tissue cells to University of Minnesota. colloidal dyes. HALDOWNEY, 10. Microscopic sections of the ovaries of the spermophile (citellus) showing secretory granules and lipoids characteristic of the periods of the annual dioestrus cycle. DELLAGAYDRIPS (Introduced by Thomas G. Lee), Institute of Anatomy, University of Minnesota. 11. Demonstrations illustrating hematogenesis in the embryonic liver as correlated with different stage in hepatic development. V. E. EMMEL, University of Illinois Medical School. 12. Further observations concerning the relation of the aortic cell clusters and degenerating aortic rami. The Demonstrations consist of a series of sections and drawings showing: ( a ) The Intimate Association of Aortic Cell Clusters and Arterial Cell Masses in Aortic Rami. ( b ) Aortic Cell Clusters in Relation t o Atrophying Roots of the Superior Mesenteric Artery. (c) The Relation of Cell Clusters Within the Lumen of the Superior Mesenteric Artery 'to Degenerating Aortic Rami. V. E. EMMEL, University of Illinois Medical School. F. W. HEAGEY, Department of Anatomy, Creighton University. This material was collected by the Lang-Chapin expedition of the American Museum of Natural History in Belgian Congo, Africa. It has been loaned to the Department of Anatomy of Crcighton University for study. This collection coiisists of six compIete skeletons of Okapia ranging in size from an embryo 120 mm. in length to a young individual that has attained ahout one-third the adult growth. 13. The growth of the limb-skeleton of Olcapia Johnstoni. PROCEEDINGS 55 14. Further experiments with the eflect of heat upon the chromosomes of Cumingia. MARGARETM. HOSKINS,New York University and Bellevue Hospital Medical College. 15. Specimens and slides of further experiments with thyroidectomy in Amphibia. ( R a n a Sylvatica.) E. R. HOSKINSand M. M. HOSKINS, New York University and pellevue Hospital Medical College. 16. A’wax model of the left half of the medulla oblongata of Squalus acanthias (“pup” stage), showing a n analysis of the cranial ganglia. SALLYP. HUGHES,Zoological Laboratory, Grinnell College. 17. The e$ect of inanition upon the growth and structure of the suprarenal gland in the albino rat. C. M. JACKSON, Institute of Anatomy, University of Minnesota. 18. A wax-cast model of the human nasal cavity and paranasal sinuses. C. M. JACKSON and C. E. CONWOR, Institute of Anatomy, University of Minnesota. A. E. JENKS, (by invitation), Department of Anthropology, University of Minnesota. 19. An instrument for the measurement of human hairs. do. Autonomic ganglia of the frog before and after degeneration of the preganglionic Jibres. S . E. JOHNSON, Northwestern University Medical School. 21. ( a ) Neurological methods; celloidin sections; staining; mounting and storing sections. (b) Nucleus caudatus and other recent forebrain University of Minnesota. studies. J. B. JOHNSTON, 23. The implantation of the ovum and early development in the rodent dipodomys. THOMAS G. LEE, Institute of Anatomy, University of Minnesota. 23. X-ray photographs of injected blood vessels as illustrated by stereorentgenograms of the lung. W. s. MILLER,University of Wisconsin. By slight modification of Gage’s corn starch injection mash using various pigments different degrees of density may be obtained. 24. Certain persistent units of anatomical structure. ROYL. MOODIE, University of Illinois. 25. The arterial supply of the human hypophysis. STUARTMUDD, (introduced by Dr. R. J. Terry), Washington University Medical School, St. Louis. Three methods are being used: a) Injection with thin celloidin and corrosion by artificial gastric juice-somewhat unsatisfactory be- 56 AMERICAN ASSOCIATION O F ANATOMISTS cause of difficulty of injecting finer vessels, and because relations of arteries to tissues are not preserved; b) wax reconstructions of thick colloidin sections of foetal specimens-sections not yet studied; c) dissection under binocular of gelatin-injected vessels. Brains for dissection are injected through the common carotid, with contra-lateral carotid, both vertebrala and external and internal jugular veins ligatured. Robin's Prussian blue and carmin have been used. The base of the brain in the region of the sella turcica and the underlying bone are removed and preserved in formalin. The brain and meninges are carefully freed from the underlying bone, dehydrated and cleared in cedar oil. They may then best be dissected under oil of wintergreen with a binocular. The brains are dissected through their underlying meninges successively upon two planes: 1) a n intradural plane, comprising the internal carotids and their branches within the cavernous sinus; 2) a subdural plane comprising the circle of Willis and its branches. Four brains only in the intradural plane have thus far been dissected. I n each of these four brains there are found, arising from each internal carotid a t its firsl; and superiorly convex flexure in the cavernous sinus, an artery of approximately one t o two millimeters in diameter which quickly breaks u p into several somewhat variable branches. These branches, together with an inconstant artery which may arise from the carotid in the sinus cavernosus more anteriorly, supply the semilunar ganglion, the third, fourth, fifth and sixth nerves in this region and the contiguous dura mater. One of the branches on each side, ramifying, courses between the layers of the dura across the posterior lobe; twigs are sent also t o the dura and may even be sent to the anterior lobe. The branch described is probably sufficient t o supply the posterior lobe, but apparently does not form a considerable element in tho supply of the highly vascular anterior lobe. 26. ( a ) The fetal development of the mammary gland in male and female albino rats. (Wax reconstructions and stained sections.) ( 6 ) The development of the mammary gland in male and female albino rats from birth to ten weeks of age. (Wax reconstruction, cleared preparation and stained sections.) J. A. MYERS,Institute of Anatomy, University of Minnwota. 27. Preparations and drawings illustrating the structure of the truncus sympathicus rami communicantes and splanchnic nerves in the cat. S . W. RANSON,Northwestern University Medical School. 28. Histological preparations showing the cyclic changes in the interstitial cells of the testis and of the ovary in the woodchuck (Marmota Institute of Anatomy, University of monax). A. T. RAYMUSSEN, Minnesota. PROCEEDINGS 57 DANIELG. REVELL,Department of Anatomy, University of Alberta. Photographs, roentgenograms and sections showing deduplications and deficiencies in chick, pig, human and other specimens. 29. Monsters of excess and of defect. 30. O n the growth of the various organs of the body during fetal life. R. E. SCAMMON, 1ns.titute of Anatomy, University of Minnesota. Field graphs and curves of the rate of growth of the various organs of the *body during the greater part of fetal life, based upon material from autopsies in the Institute of Pathology of the University of Minnesota and on cases collected from the literature. Tables showing the average weight and the degree of variation in the weight of the principal organs of the body at birth. 31. Sections showing the origin, development and finer structure of the Institute of Anatomy, Unisucking-pad z'n man. R. E. SCAMMON, versity of Minnesota. 3.2. Various parts of the brain in normal and underfed albino rat at dif- Institute of Anatomy, University of ferent ages. C. A. STEWART, Minnesota. 33. V a n W i j h e preparations of the primordial cranium of the cat. R. J. TERRY, Washington University Medical School. Embryos measuring 10.5, 15, 24 and 30 mm. in length, prepared by Van Wijhe's method of staining and clearing, reveal in the clearest way the beginning, direction and extent of the processes of cartilage formation. Of special interest in these specimens is the evidence given of independence of chondrification of the otic capsule, parts in the cranial side wall and elements of the ethmoidal skeleton. In the specimen of 10.5 mm. may be seen the hypophyseal cartilage, the beginning of the otic capsule, Meckel's cartilage, parachordal plate and lateral occipital arches. The preparation of the 15 mm. embryo shows the septal, paratectal and paranasal cartilages, the ala orbitalis, ala temporalis, commissura orbito-parietalis, basal plate, hypoglossal foramen and lamina parietalis. The cranium of the 24 mm. embryo is of special interest in giving evidence of the relations of the suprafacial commissure to the parietal plate. Chondrification of the cranium has reached its mazimum in the 30 mm. specimen. 34. A teaching model of a 10 mm. pig embryo. IVANE. WALLIN, Marquette University. 55. Models illustrating the early development of the liver and hepatic (introduced by E. A. ducts in the mouse. H. W. WELLMERLING, Baumgartner) , Washington University Medical School. 58 AMERICAN ASSOCIATION O F ANATOMISTS The liver in 3 mm. embryos is a wide outgrowth of the gut with many small projections. Ventml to the hepatic portion is the small, rounded adage of the gar1 bladder, Hammar's pars cystica of the hepatic anlage. The common duct in 3.5 mm. embryo has a wide dorsal connection with the gut and bears on its caudal surface the anlage of the ventral pancreas and a largc gall bladder. Hepatic trabeculae are attached to the cranial surface of the cystic duct, as well as to the hepatic duct proper which extends a few sections from this surface at the level of the ventral pancreas. 'In a 6 mm. embryo the ventral pancreas extends caudalward and to the right of the mid-line of the gut. The common duct has lengthened, and gives rise t o the cystic duct which extends ventrally. A 10 mm. embryo show8 great growth of the duct system. The common duct, as well as the dorsal pancreatic duct, arises from the dorsal surface of the gut. A short distance from its origin the common duct gives off caudally the ventral pancreatic duct, then turns cranialward and gives ofY hepatic ducts in all directions. Beyond this region it divides into two; a small left and a large right duct, from the ventral surface of which a long cystic duct extends ventrally and to the left. From the anterior end of the. two hepatic ducts smaller ducts pass outward giving ofl trabeculae. Some of these smaller ducts projecting medially from the two larger ducts anastornose. 36. Graphic reconstruction of the cranial nerves of the common garter University of Nebrqka, College of Medicine. snake. W. A. WILLARD, 37. Specimens showing the diferentiation of angioblasts, the method of the formation of the lumen of biood-vessels and the diferentiation of red- blood-cells as made out in the living chick. FLORENCE R. SABIN, Johns Hopliins Medical School.