TOPOGRAPHY OF THE THORAX AND ABDOMEN 3 



from sections, of charts showing the positions of the organs 

 of the body that there was any advance beyond what 

 Froriep had announced nearly seventy years before. 



Henke's method is, briefly, to establish a vertical line, 

 representing the median sagittal plane of the body, crossed 

 by horizontal lines representing the positions of the sections 

 from which the projection is to be made. Any point in any 

 section can be accurately projected upon the chart by using 

 the vertical line and the proper horizontal line as coordi- 

 nates. 



This method of recording observations marks the be- 

 ginning of a new epoch in topographic anatomy, because it 

 puts each part into a concrete form and thus lessens the lia- 

 bility of error. At the present time, all writers on topo- 

 graphic anatomy give the section method a prominent place 

 as a method of study. 



Not only has the method of recording observations 

 changed but also the method of preparation of the sections. 

 The original method (that used by all the anatomists re- 

 ferred to) was to freeze the body thoroughly and while 

 frozen to saw it into sections of the desired shape and thick- 

 ness. The sections were then placed in strong alcohol and 

 allowed to thaw slowly. The results were not entirely 

 satisfactory since the organs did not always become suffi- 

 ciently firm to retain their exact form and relations, and the 

 shrinkage was unequal in the different organs. Moreover 

 the surfaces were somewhat rough from the sawing so that 

 it was difficult to recognize the finer structures. 



A distinct step in advance was made when formalin, as 

 a hardening reagent, was introduced into the methods of 



