1878.] 



the Temperature of the Head. 



169 



thence continued by the outer borders of the malar bones to the points 

 of origin of the lateral boundaries. 



The part of the head embraced by the anterior region is, therefore, 

 that which would be cut off anteriorly by a transverse and vertical 

 section, made parallel to the plane specified, between the angles formed 

 by the frontal and zygomatic processes of the malar bones of the two 

 sides. 



Middle Region. 



The middle region is bounded anteriorly by the lateral and superior 

 boundaries of the anterior region. 



The posterior boundary is formed by a line passing over the top of 

 the head parallel to the anterior boundary, uniting the extremities of 

 the mastoid processes of the two sides. 



The inferior boundaries commencing at the terminations of the 

 inferior boundary of the anterior region, follow the upper borders of 

 the zygomatic processes of the temporal bones, pass behind the ears, 

 and follow the anterior borders of the mastoid processes to their 

 extremities. 



Posterior Region. 



The posterior region has for its superior and lateral boundaries the 

 posterior boundary of the middle region. 



The inferior boundary is formed by the posterior borders of the 

 mastoid processes and by the superior curved line of the occipital bone. 



The longitudinal median line of the head divides each of the three 

 regions into right and left symmetrical halves. 



In the present communication we have only to do with the anterior 

 region. 



The anterior region is thus subdivided : — 



Commencing at the inferior boundary, each lateral half is divided 

 into six parts by five equidistant horizontal lines drawn from the 

 median line to the lateral limit. The tracts thus marked off are 

 designated tiers, and are numbered from 1 to 6, commencing at the 

 inferior boundary. Further in each lateral half four equidistant ver- 

 tical lines are drawn upward parallel to the median line, from the 

 lower limit to the superior boundary, thus dividing each tier into 

 smaller spaces. In the first four tiers these spaces are five in number ; 

 but in the fifth and sixth tiers, the convergence, over the top of the 

 head, of the lateral limits diminishes the length of the tier, and re- 

 duces the number of spaces to four in the fifth tier and to three in the 

 sixth tier. These spaces are designated districts, and are numbered 

 from 1 to 5 outward from the median line. The tiers are marked off 

 by means of a string coated with coloured chalk. 



As the method of measuring off the tiers and districts by equidistant 



