124 



Solution B. — Iodine, 1 part. Potassium Iodide, 3 parts. Distilled water, 

 300 parts. 



Solution C. — Saturated watery solution of vesuvin or bismarck brown. 

 The sections are immersed in absolute alcohol for a few minutes, and then 

 placed in Solution A for 1-3 minutes ; washed for a few moments in absolute 

 alcohol, and transferred to Solution B, in which they remain for 1-3 

 minutes. They are then again washed in alcohol, and placed in Solution C 

 for several minutes ; washed in distilled water, dehydrated in alcohol, 

 clarified in several changes of oil of cloves, and mounted in Canada balsam. 

 This method is by far the best for staining bacteria with which I am 

 acquainted, and if the various steps are properly carried out the bacteria 

 should be stained of a dark violet colour, and stand out in striking contrast 

 with the tissue elements, which are stained light brown. 



If tubercle bacilli are to be stained by this method, the sections should 

 be left in Solution A for 24 hours instead of a few minutes, and the other 

 steps cai-ried out in the manner which I have just described. The result is 

 far superior to that which was obtained by the method of staining the sec- 

 tions in a fuchsin-anilin solution, treating them with nitric acid, and con- 

 trast staining them with methyl blue. 



Let me in conclusion remind you that bacteria are not of interest solely 

 to the pathologist, but that, entirely apart from pathology, much remains 

 yet to be learned of their life history, and development, and the precise 

 nature of the fermentative processes to which they give rise. Why do 

 micrococci generally grow in a solid mass in meat jelly, while many bacilli 

 liquify the same medium ? What is the nature of the pigment in the chromo- 

 genous bacteria ? What changes occur in the blood under the influence of 

 the bacillus anthracis? Such are a few of the many questions which still 

 remain to be solved by patient and untiring chemical investigation. 



The various processes illustrative of the lecture were carried out by Mr. 

 Thurston, assisted by Mr. J. W. Groves, and, on the conclusion of the demon, 

 stration, a hearty vote of thanks was aocorded to these gentlemen, on the 

 motion of Mr. A. D. Michael. 



The following objects were exhibited in the Library : — 



Fairy shrimp Chirocephalus diajjhanus ... Mr. F. W. Andrew. 



Web of house spider Aviaurobius similis ... Mr. F. Enock. 

 LojjIlojms crystalinus ... ... ... ... Mr. J. D. Hardy. 



Gamasus coleojptratorum ... ... ... Mr. G. E. Mainland. 



Disparipes Bombi ... ... ... ... „ „ „ 



Asteromphalus Humboldtii ... ... ... Mr. H. Morland. 



Condijlostoma stagnate ... ... ... ... Mr. R. T. G. Nevins. 



Cuticle of Fuschia ... ... ... ... Mr. C. Le Pelley. 



Bacillus of splenic fever ... ... ... Mr. E. Thurston. 



Type slide of 100 species of diatoms... ... Mr W. Watson. 



Attendance — Members, 68; Visitors, 11. 



