FEB 6 1899 



I. 



WAX MODELING FROM MICROSCOPIC SECTIONS. 

 By W. E. Wells. 



[Read before the Scientific Association at its Regular Meeting, fan. i6, iSg'/.'] 



In the morphological and comparative study of organic structures 

 the value of wax modeling cannot be over-estimated. In view of this 

 fact, and owing to the apparent scarcity of literature on the subject, a 

 brief oudine of methods employed in the Biological Laboratories of 

 Denison University, is here given. 



Models may be divided into two classes : wax or clay models, 

 which are moulded by hand, and wax and card-board models, which 

 are constructed from microscopic sections. 



Models of the first class are built up from observed form in gross 

 dissection and will not be described in detail here. 



Wax Modeling /rom Seciiofis. This method consists, essentially, in 

 constructing enlarged patterns of a series of microscopic sections, and 

 from these patterns constructing a model which will represent the origi- 

 nal unsectioned tissue, but on a greatly enlarged scale. 



Wax. The material best suited for such modeling is ordinary 

 beeswax. The beeswax of commerce is either bleached or unbleached. 

 The unbleached, by virtue of its greater plastic property, is better suit- 

 ed for modeling. The least tendency toward brittleness becomes a 

 source of trouble in the cutting process. 



A medium sized model, measuring in its three dimensions, 6x3x2 

 inches, requires about one pound of wax, including necessary waste. 



Commercial yellow wax may be had at a cost of from 40c. to 60c. 

 a pound. Bausch & Lomb furnish a special modeling wax at 55c. a 

 pound, in bulk, or in sheets of uniform thickness, at $1.12 a dozen. 



Wax Sheets — Method for Casting. The wax sheets on which the 

 sectional drawings are to be traced, must be of definite thickness, for 

 if the length and breadth be magnified, the thickness must also be in 

 direct proportion. 



In rough modeling where general morphological relations only are 

 sought, the thickness may be estimated, and sheets made accordingly. 



