CHOICE OF A METHOD. 173 



I strongly recommend the reader not to neglect this simple 

 method, which is capable of sometimes rendering services 

 which no other method can. Those who have to do work 

 with objects so small that their position can only be made out 

 with the aid of a powerful lens ought to know how to arrange 

 an object with a heated needle under a dissecting microscope^ 

 or on the object-carrier of the microtome. 



[In the first edition this procedure was attributed to 

 KINGSLEY. It appears to have been first published by BORN, 

 see " Die Plattenmodellirmethode/' in Arch. f. mik. Anat., 

 1883, p. 591.] 



There remains the watch-glass method. Melt paraffin in a 

 watch-glass, and throw the object into it; or place the object 

 in the watch-glass, add solid paraffin, and heat. After the 

 mass has hardened, cut out a block containing the object 

 (this is of course applicable to other masses, such as celloidin) . 

 If paraffin be used you may, instead of cutting out a block, 

 turn out the whole mass of paraffin by simply warming rapidly 

 the bottom of the glass, To facilitate the removal of the 

 mass some persons lubricate the watch-glass before pouring 

 in the mass. To do this a drop of glycerin should be 

 smeared over it and wiped off with a cloth until hardly a 

 trace of it remains. 



As regards the merits of the watch-glass process, I wish to 

 say that, as regards small objects at all events, I consider it 

 the very best process of any. 



274. Choice of a Method. Amongst the very various methods 

 of imbedding that have been proposed two are pre-eminently 

 important the paraffin method for small objects, and the 

 celloidin or collodion method for large objects. 



The subject of the respective merits of paraffin and celloidin 

 still affords matter for discussion to some persons. The case, 

 however, seems to be a very simple one. Celloidin does not 

 afford by a long way the thinnest sections that are obtainable 

 with small objects. For such objects it is, therefore, not equal 

 to the demands made by modern minute anatomy, and paraffin 

 must be taken. On the other hand, paraffin (as at present 

 employed) will only cut very thin sections with small objects; 

 with objects of 7 millimetres diameter you cannot get with 

 paraffin thinner sections than you can with celloidin; and if 



