324 Dr. A. M. Marshall on the Olfactory Nerve [Feb. 13, 



and whenever there is union not very firm, and may also modify some 

 of our opinions on atomic weights and the motion of gases. 



Of course, I cannot pretend to give the result of these results ; but 

 as we have here the building up of a molecule by volumes, so as 

 to form an equivalent of physical combination analogous to the 

 chemical equivalent, it is impossible to avoid seeing that it indicates 

 the possibility of our present equivalents being made up in a similar 

 manner. 



I did not expect these numbers ; but T certainly, as my previous 

 paper showed, had in full view a necessity for some connexion 

 between physical and chemical phenomena more decided than we 

 possessed. 



February 13, 1879. 



W. SPOTTISWOODE, M.A., D.C.L., President, in the Chair. 



The Presents received were laid on the table and thanks ordered for 

 them. 



The - following Papers were read : — 



I. " Note on the Development of the Olfactory Nerve and Ol- 

 factory Organ of Vertebrates." By A. Milnes Marshall, 

 M.A., D.Sc, Fellow of St. John's College, Cambridge. 

 Communicated by W. S. SAVORY, F.R.S., Surgeon to and 

 Lecturer on Surgery at St. Bartholomew's Hospital. Re- 

 ceived January 30, 1879. 



In the course of an investigation into the development of the 

 cranial rerves of the chick, certain facts came to light indicating that 

 the olfactory nerve, instead of being, as usually described, a structure 

 differing totally in its mode of origin from all the other nerves in the 

 body, in reality " exactly corresponds in mode of development and 

 in appearance with the other cranial nerves, and with the posterior 

 roots of the spinal nerves."* 



The present paper contains the results of further investigations on 

 this point ; it deals also with some features in the development of the 

 vertebrate olfactory organ,' and with certain questions of a more 

 general nature affected by the conclusions arrived at. 



* " Proc. Roy. Soc," vol. xxyi, p. 50, and " Quarterly Journal of Microscopical 

 Science," January, 1878, pp. 17-23. 



