894 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



rare pathological injections, so that it should be possible to make 

 extraordinarily thin sections without the least tearing of the cells or 

 tissues. How far the thinness of the sections can be carried is, of 

 course, different in different objects, and it is therefore difficult to lay 

 down any hard and fast rules. 



For the fulfilment of these requirements Boecker first endeavoured 



Fig. 165. 



to give to the knife the proper movement, so that it should move in 

 the same way as if guided by the hand. It appeared to him that the 

 ordinary method of moving the knife by means of a slide was not 

 sufficiently firm, and involved the inconvenience of keeping the slide 

 steady by the hand. He also decided to give the knife such a con- 

 siderable inclination that it should be nearly parallel with the direc- 

 tion of the slide. 



This attempt was successful in every respect. Two slides of 

 brass-plate are connected in such a manner that their movements 

 shall cross at right angles. If the one slide S' (Fig. 165) is moved 



