24 



on Microscopic mountings and preparation." They should be mounted 

 dry, or in balsam, and viewed as opaque or transparent objects, and 

 with the spot lens or paraboloid. There was a method of giving them 

 an enamel-like opacity by burning them on platinum foil, but whatever 

 method of mounting or illumination was adopted, all who had seen the 

 Polycystina under the microscope must allow they were very beautiful 

 and delicately sculptured objects, while the question how the creatures 

 whose shells they were, constructed such charming habitations, 

 remained among the, at present, unsolved problems of Natural History. 



The Meeting then became a Conversazione, when some exquisite 

 and beautiful specimens of Polycystina were exhibited under the 

 microscope. 



December 9th. 



ORDINARY MEETING.— DR. HALLIFAX ON " THE 

 NERVOUS SYSTEM AND ITS FUNCTIONS." 



( Continiiatioii). 



Dr. Hallifax said, at the last meetinghe endeavoured to trace the 

 different gradations of the nervous system, as they appeared through- 

 out the series of animals, beginning at the lowest ; and his object was 

 to show that, as they ascended, the complexity of the nervous system 

 kept pace with the complexity of the animal organization, and was 

 not only developed on the introduction of a new organ, but even on 

 the exaltation of an organ already existing. The insect tribes 

 approached nearer than any other of the series to the mammalian ; 

 and, by way of illustration, he would select one of the social insects, a 

 bee or a wasp, as denoting in its action the exercise of an intelligent 

 principle. In the higher forms of insects was found the cerebro-spinal 

 axis, the great central organ, consisting of the spinal cord and the 

 cerebrum. In man the cord was of great length, proceeding from the 

 cerebrum down to the lower portion of the frame, sending off, on each 

 side, throughout the system, thirty-one pairs of spinal nerves. Each 



