DRAWING WITH CAMERA 21 



For ordinary purposes a freehand drawing will 

 suffice, the scale being as nearly as possible that of the 

 object as it appears under the microscope, or larger, if 

 the object be a complicated one : whatever the scale, 

 the proportion of the several parts is to be scrupulously 

 followed. Coloured chalks, or better, light washes of 

 water-colour, may be used for distinguishing tissues of 

 different character, and in making a series of drawings 

 the same colours should be assigned to corresponding 

 tissues throughout the series. 



When drawing cell-walls of appreciable thickness, 

 they should be indicated by a double line ; solid bodies 

 should be shaded so as to give the idea of light coming 

 from one side, and in a series of drawings the side 

 selected should be maintained throughout. 



But in case of complicated networks of tissue, or where exact- 

 ness of delineation, proportion, and scale, are required, drawings 

 should be made by the help of the camera lucida. A most con- 

 venient type of camera is that of Nachet of Paris ; and it may 

 be obtained from Swift and other makers in a form adapted to 

 English microscopes. It is convenient to have it fitted with a 

 spring clip, by which it is attached to the upper extremity of the 

 tube of the microscope, while the camera itself is connected with 

 the clip by a hinged arm, so that it can be adjusted over the eye- 

 piece when in use, or when not wanted, it can be turned to one 

 side without being actually removed. 



When an object is to be drawn, it must be placed in the middle 

 of the field of the microscope, which is to be kept as usual in the 

 vertical position ; a sheet of paper or card is placed on the table 

 to the right of the microscope, and the camera adjusted over the 

 eye-piece : on looking through the camera the object will still be 

 seen, and the movable prism is then to be rotated on its axis till 

 the sheet of paper comes also into view : the object will then be 

 seen projected on the sheet of paper, and its outline maybe traced 



