722 



SCIENCE 



[N. S. Vol. XXXVII. No. i 



' ' 1 ox, broken to the yoke, 



an ox of Ibni-Sin son of Sin-imgurani, 



from Ibni-Sin 



through the agency of Kishti-Nabium, 



son of Bteru, 



Abarama (i. e., Abraham) son of Awel-Ishtar 



has hired for 1 month. 



For 1 month 



1 shekel of silver 



he will pay. 



Of it i shekel of silver 



from the hand of Abarama 



Kishti-Nabium has received. ' ' 

 The Succession of Human Types m the Glacial 

 and Interglacial Epochs of the European Pleis- 

 tocene: Henry Fairfield Osboen, D.Sc, LL.D. 

 The Flora of Bermuda (illustrated) : Stevs^ard- 

 SON Brown. Introduced by Professor Henry 

 Kraemer. 



In the studies of the land flora of Bermuda 

 which have been carried on since September, 1905, 

 in cooperation with the New York Botanical Gar- 

 den, the islands have been visited during parts at 

 least of aU the months of the year except January, 

 July and October. More than 1,450 separate col- 

 lections of plants have been made from all parts 

 of the archipelago with the exception of a few of 

 the smaller islands which are only rocks with but 

 little vegetation. The native species of flowering 

 plants and ferns exclusive of the endemic forms 

 number 155, all of which are identical with those 

 existing on the American mainland or the west 

 Indian islands. The fourteen endemic species, 

 four of which have been added through these 

 studies, are all more or less nearly related to those 

 of the southeastern United States, West Indies or 

 tropical continental America and probably derived 

 from such ancestors by modification during long 

 periods of isolation. It would appear, therefore, 

 that the greater portion of the native flora has 

 come to Bermuda from the southwest through the 

 agency of ocean currents, hurricane winds and 

 migratory birds, of which a considerable number 

 of species visit the islands regularly each year. 

 A New Type of Sewage Disposal Tank: William 



Pitt Mason, M.D., LL.D. 

 Determination of Uranium and Vanadium in Car- 

 notite Ores of Colorado: Andrew A. Blair. 



Friday, April IS — Morning Session 



William W. Keen, M.D., LL.D., president, 



in the chair 



The Uses and Needs of Selachology {The Study 



of SharTcs and Mays) : Bdrt G. Wilder, M.D. 



Interpretations of Brain Weight (illustrated) : 

 Henry H. Donaldson, Ph.D., D.Sc. 



The Correlation of Structural Development and 

 Function in the Growth of the Vertebrate 

 Nervous System (illustrated) : George E. Cog- 

 hill, Ph.D. Introduced by Dr. H. H. Donald- 

 son. 



Eecent studies in comparative neurology have 

 resolved the central nervous system of vertebrates 

 into four longitudinal divisions which are severally 

 functional units. Among lower vertebrates the 

 relative development of these divisions, the somatic 

 sensory, the visceral sensory, the somatic motor 

 and the visceral motor, has been in a significant 

 manner correlated with the behavior of the species. 

 Such correlations by the comparative method 

 formed the point of departure for this study on 

 the correlation of the behavior of embryos with 

 the developing structures in the growth of the 

 nervous system. 



Embryos of Amphibia are found to be somatic 

 sensory and somatic motor organisms. They give 

 no evidence of visceral nervous functions until 

 after the locomotor mechanism has become estab- 

 lished. This mechanism develops out of three 

 types of nerve cells, sensory, associative and 

 motor. The sensory system of the trunk is formed 

 of the giant ganglion cells of the spinal cord, 

 which connect with the skin by means of dendritic 

 processes. This sensory system of the trunk be- 

 comes functional earlier than does the sensory sys- 

 tem of the head, which is the definitive system of 

 cranial nerves. The associative cells form a ven- 

 tral commissure between the sensory cells of one 

 side and the motor cells of the other. The motor 

 cells hold a relatively ventral position in the spinal 

 cord and lower portion of the brain. They form 

 a continuous motor column and tract on either 

 sid« and connect with the muscles by means of 

 collaterals from their axones. The development of 

 this system of reflex arcs with a single final com- 

 mon path on either side may be distinctly cor- 

 related with the development of the behavior of 

 the embryo up till the time when locomotion 

 becomes perfectly established. 



Some of the more general results of this method 

 of study are: (1) the demonstration of the nature 

 of the primary reflex arc of the vertebrate ner- 

 vous system, (2) the discovery of the adaptive 

 nature of the early reflexes when considered from 

 the phylogenetic point of view, (3) proof that 

 the final common path of the most primitive re- 

 flexes is elaborated into the nervous mechanism of 

 locomotion, (4) the explanation of the typical be- 



