Appendix. 157 



The holder and collodion block are now immersed for a 

 few minutes in chloroform, or long enough for them to 

 become firmly united. 



The object-holder is finally screwed between the jaws of 

 the microtome, and covered, by means of a camePs-hair 

 brush, with oil of thyme. The microtome knife is flooded 

 with the same oil. 



After a few sections have been cut from the block of col- 

 lodion, the relative position of the plane of the knife to the 

 axis of the object can be definitely established, and the 

 object definitely oriented. 



The sections are now cut and may be at once transferred 

 to the slide, covered with balsam/ and mounted ; or if they 

 are not immediately needed they may be kept indefinitely, 

 together with the block, in a vial of thyme oil. 



