402 



NA TURE 



[August 24, 1905 



came the interarticular disc, as can be seen in 

 echidna. By means of a model he demonstrated 

 the manner in which a new joint could be developed 

 without leading to a disturbance of the function of 

 mastication, thus leaving the quadrate to form one 

 of the auditory ossicles (hammer). It must be ad- 

 mitted that Gaupp's theory explains the embryo- 

 logical phenomena, and clearly me', with general 

 acceptance by the members of the congress. Prof. 

 Eugen Fischer, of Freiburg, pointed out that the 

 theory explained the presence of cartilage which he 

 had found in the developing coronoid and condylar 

 processes of the jaw in the mole and apes. A model of 

 an early developmental stage of the human mandible 

 was shown by Dr. Alexander Low, of Aberdeen, 

 who also demonstrated a special formation of car- 

 tilage, independent of Meckels, in the condylar and 

 coronoid processes of the human jaw — facts in favour 

 of Gaupp's hypothesis. In the opinion of the writer 

 of this report, this vexed question is not yet settled, 

 nor is it likely to be so long as anatomists seek to 

 derive the mammalian from the reptilian type of 

 mandible. 



Ten communications dealt with the structure or 

 development of nerve cells. One of these was a 

 paper by Prof. .\. Donaggio, of Naples, " II reticolo 

 neurofibrillare della cellule nervosa dei Vertebrata 

 (con demostrazione di preparati microscopici)," which 

 revealed the energy and fire which Continental 

 anatomists can throw into their work. Prof. Ramon 

 y Cajal, of Madrid, also brought to the congress 

 specimens to demonstrate the direct continuity of the 

 •neuro-fibrillar network of the nerve cell with the den- 

 drites on the one hand and the axon on the other. 

 He had placed his microscopes and specimens on a 

 window-ledge of a passage leading to the laboratory 

 where Donaggio gave an enthusiastic demonstration 

 to an intent circle of listeners. Cajal suddenly joined 

 the circle and gave a direct contradiction to some 

 statement of Donaggio. A lively scene followed ; 

 Cajal fetched his microscopes and specimens one by 

 one from the passage and placed them impetuously 

 before Donaggio. It was hard to ascertain the exact 

 point in dispute, but it was subsequently discovered 

 that it was a matter of thickness of section, Cajal 

 maintaining that Donaggio's sections were too thin 

 to demonstrate the relations of the neuro-fibrillar net- 

 work of the nerve cell, while, of course, Donaggio 

 regarded those of his opponent as too thick. The 

 dispute was amicabl)' settled by the discovery that 

 both meant the same thing, namely, that the neuro- 

 fibrillar network of the nerve cell was directly con- 

 tinuous with dendrites and axon. 



The question of the development and regeneration 

 of nerve cells again came up for discussion. Dr. 

 John Cameron showed excellent photomicrographs 

 of the developing optic and spinal nerve fibres in 

 amphibians and birds which he believed to be both 

 of central and peripheral origin. Optic fibres he 

 regarded as direct prolongations from the nuclei of 

 the retinal ganglion cells. Specimens were shown 

 by Dr. Alfred Kohn, of Prague, demonstrating that 

 the cells which go to the formation of a nerve, both 

 fibre and sheath, are derived from the central nervous 

 system — a histological confirmation of Harrison's 

 clever experiment. Prof. Barfurth, of Rostock, pro- 

 duced the results of experiments on regeneration of 

 nerve fibres made by C. F. Walter, and concluded 

 that the axis cylinders could be produced by the 

 cells of the nerve sheath. 



Dr. George Streeter exhibited a series of models 

 showing the development of the acoustic ganglion in 

 human embryos. The cochlear ganglion is separated 

 from the vestibular ganglion during development, 



NO. 1869, VOL. 72] 



and the association of the cochlear nerve with 

 the nerve to the posterior ampulla is merely 

 fortuitous ; Dr. Giuseppe Levi, of Florence, gave 

 an account of the various forms of cells found in the 

 ganglia of the spinal nerves in developing pigeons. 

 In another communication this author showed that 

 ganglion cells vary in size with the size of the 

 animal in which they occur; other cells are not 

 affected by the size of the animal. Dr. E. B. 

 Jamieson e.xhibited an excellent series of dissections 

 of the brain, showing how various nerve tracts, 

 usually seen only in section, can be demonstrated in 

 their complete extent by means of scalpel and forceps. 



Several contributions were made to our knowledge 

 of blood corpuscles. Dr. T. H. Bryce gave an ac- 

 count of the development of the thymus gland in 

 Lepidosiren, and showed that leucocytes were pre- 

 sent before this gland was developed, and that, 

 therefore. Beard's theory of the thymus being the 

 primary source of leucocytes could not be entertained. 

 VVeidenreich, of Strassburg, traced the origin of all 

 forms of white blood corpuscles from a common 

 mononuclear cell, which was similar to, if not iden- 

 tical with, connective tissue corpuscles. With this 

 conclusion Dr. Bryce agreed. Prof. Jolly, of Paris, 

 described the formation of the mammalian red blood 

 corpuscle by the gradual absorption and disappear- 

 ance of the nucleus, not by an extrusion as is usually 

 supposed. A research into the changes in the 

 thymus gland which take place with age led Prof. 

 Hammar, of Upsala, to conclude that the lymphoid 

 tissue of that gland reached its ma.ximum development 

 in the years of puberty. Analogous results were ob- 

 tained by Dr. R. J. A. Berry and Dr. Lack, of Edin- 

 burgh, regarding the development of the lymphoid 

 tissue of the vermiform appendix. Using the average 

 number of lymphoid follicles seen in sections of the 

 appendix as an index of the development of the 

 lymphoid tissue, they concluded that the maximum 

 number (7) was found about the twentieth year, every 

 subsequent decade leading to a decrease in the num- 

 ber of follicles. 



Very few of the papers dealt with the naked-eye 

 structure of the human body, or had a direct bearing 

 on the problems which interest the surgeon or 

 clinician — a very remarkable fact when one con- 

 siders that the vast majority of the members of the 

 congress are teachers of medical students. To this 

 limited group of communications may be assigned 

 the paper by Prof. Symington on the relations of the 

 deeper parts of the brain to the surface and Prof. 

 Cunningham's further observations on the fcrm of 

 the stomach, with special reference to hour-glass 

 stomach. Papers belonging to this section were 

 given by Chaine, Ledouble, Broman, Delmas, Gilis, 

 Steida, and Poirier. 



Contributions to physical anthropology were also 

 few in number. Dr. Wright, of Birmingham, dealt 

 with the characters of the men buried in the round 

 barrows of Yorkshire, and found that they were 

 identical with the men obtained from prehistoric 

 graves in the neighbourhood of Fribourg, Lussane, 

 and Berne. Englishmen of to-dav are rather longer- 

 headed than the men who were buried in the round 

 barrows of Yorkshire, a fact which Dr. Wright ex- 

 plained by the invasion and intermixture of the long- 

 headed Scandinavians with the men of the round bar- 

 row age. Prof. Eugen Fischer dealt with the de- 

 posit of pigment beneath the conjunctiva. It occurs 

 in mammals generally, and in all primates and 

 races of men save Europeans, in whom the sub- 

 conjunctival tissue is free from pigment except under 

 certain pathological conditions. 



Some very remarkable specimens — showing exqui- 



