15 



seed vessels. The lecturer pointed out the importance of having the 

 specimen in fruit, and described the method of examining the seed. He 

 also referred to several of the anomalous species belonging to the order, 

 and illustrated his remarks throughout by numerous drawings on the 

 blackboard. 



Meeting held in the Lecture Theatre and Laboratory of the Medical 

 School, Park Street, March 18th, 1889. Professor De Burgh Birch, 

 M.D., CM., F.R.S.E., President, in the chair. 



DEMONSTRATION OF METHODS OF INJECTION. 

 PROFESSOR BIRCH. 



Injection, as a method of preserving animal tissue, was shown not to be 

 by any means a new process. It was practised to some extent by the ancients 

 when embalming bodies. In medical science also it dates back a very con- 

 siderable period, but by a method now quite superseded. Mercury, until 

 somewhat recent years, was used, which had the disadvantage of desti'oying 

 minute detail of structure. This was shown by a number of exhibits from 

 the museum of the School. The method now practised is by means of 

 coloured fluids, which are of a preservative nature and obviate the 

 obliteration of minutiae of structure ; and further, most successfully bring 

 out into more immediate notice these details. This was illustrated by 

 injected specimens of epidermis, intestinal wall, and also of bone. The 

 President, in demonstrating the principal methods of use, divided the 

 subject under three heads : — (1) That of filling an organ with a preserva- 

 tive fluid, which afterwards solidifies, fixing it in a dilated form as in life ; 

 (2) That of fixing blood vessels so as to demonstrate their course through- 

 out the body ; (3) Interstitial injection. A number of formulae were given 

 for the coloured preserving and fixing media in general use, e.g., carmine 

 and Prussian blue, which are forced when in a liquid state by means of 

 suitable apparatus into the vessel it is desired to demonstrate or trace out. 

 Demonstrations in the three above mentioned methods were made upon 

 the rabbit, and were most clearly shown. 



Meeting held in the Club's Rooms, 80, Municipal Buildings, March 

 25th, 1889. J. Charters Birch, L.D.S., in the chair. 



ON VARIATION IN LEPIDOFTERA. 

 » HENRY MARSH, F.R.C.I. 



After briefly reviewing the state of knowledge on the subject, the lecturer 

 discussed some of the causes of variation and modes under which variation 

 was produced, and the classes into which these variations are divided. 

 The two great families are the "aberrational" and "^ constant" variations, 

 or as they are scientifically called heteromorphisms and orthopcecilisms. 

 Under the former were classed : albinism or white variation ; xanthism or 



