47 



but a great deal of time was lost by tbis metbod, and a certain 

 amount of rougb detail as well as tbe outline could be done 

 witb the camera in a much shorter time. He thought, how- 

 ever, that this was a matter upon which one man could not be 

 taken as a rule for another. Many persons had a difficulty in 

 seeing the paper and the object equally well at the same time, 

 and a man who was a good draughtsman would naturally do 

 better than one who was not, and there was also a good deal in 

 the idiosyncrasy of the individual eye. Personally he might 

 say that he preferred the method with ruled lines. 



Mr. Rousselet said he had a home-made camera, which he 

 found to answer very well. A small mirror of speculum metal 

 reflected the image upon a cover-glass, through which the paper 

 was seen. The image in this case was not reversed. The plan 

 was Mr. Usher's invention. 



The thanks of the meeting were voted to the President for 

 his communication. 



The President intimated that there was nothing further upon 

 the agenda paper, but as he saw Prof. Chas. Stewart present he 

 ventured to ask if he would favour them with a few remarks. 



Prof. Stewart said that when he came into the room he had 

 no expectation of being called upon to speak, but as the 

 President had done so he would in response say a few words 

 upon what was to be seen in one particular section of the 

 Museum with which he was more especially connected, and he 

 thought it possible that some persons present might be interested 

 in the structural varieties of fish bones. In the case of fish 

 which had frames of rigid structure, they found these to be 

 composed of a substance which was different in many respects 

 from such bone as they found it in mammals, although 

 it was rather difficult not to regard it as bone. When examined 

 under the microscope it was found to be wanting in the 

 familiar so-called bone-corpuscles ; it had a somewhat fibrillated 

 matrix, and in that matrix were rows of large spaces much 

 larger than the ordinary haversian canals. These certainly 

 were not blood-vessels, and they did not contain cells, but if 

 they were hardened and sections were taken they were found to 

 contain fine granular material, but in not one which he had 

 examined had he ever succeeded in finding either a cell or a 

 blood-vessel. The cod, haddock, and fish of that class all had this 

 kind of bone. In other classes of fish a very different structure 



