789 



d. Ms. 1. : 0.0.1.0. 



d. Ms. r. : 0.1.0.0.0.1.1.0. 



d.Homo. 1.: 0.1.0.0.0.0.1.2.1.0.0.1.0.1.0.0.0.1.0.0.1.1.0.1.1.0.0.0.0. 



0.1.2.1.2.3.1.0.0. 

 d.West. 1. : 4.3.3.4.5.4.3.3.5.2.3.4.6.2.3.3.4.3.2.2. 

 d Gb. 1. : 0.0.3.1.1.1.2.1.2.4.1.0.1.2.0.1.2.0.3.0.1.2.3.2.1.1.4.5.4. 



1.3.4.4.2.2.2.3.3.2.3.1.3.3.1.1.2.1. 



We mast not, of course, stop at these absolute tigures, as we 

 wish to know how many giant cells were in each case present in 

 the whole cortical content. As this cortical content is difficult to 

 determine and on account of the fact that all the cases furnished different 

 numbers of sections, it was tried to find a relative value, repre- 

 senting the mutual relation of all the cases. 



For this purpose the relative cortical content was determined by 

 transferring all sections on thin cardboard by means of a drawing 

 prism, the same magnification being always applied. Care was taken 

 to omit the medullar portions. Next the drawings of all these parts 

 of the cortex on paper were cut out, after which they were weighed 

 for each case separately, so that a cortical content was obtained, 

 proportional to the weight of the paper sections. 



Since these weights were unequal and therefore could not yet be 

 compared, a paper weight of one gram was taken as unit. From a. 

 the sum of the numbers of giant cells observed, and h. the weight 

 of paper of all cortical sections, it was now possible to determine for 

 each particular case how many giant cells were found per gram of 

 relative cortical content and these final values could be compared 

 among each other. 



The following results were obtained : (See table «p. 790). 



The problem is now . to determine from these results what the 

 variability is of the number of these giant cells. In this determination 

 the normal portions were separated from those furnished by the 

 deaf-mute, and for both categories the method given by Johannsen ^) 

 was applied. 



Let us begin with the normal cases. 



First of all the middle-value was here calculated from our data, 

 i.e. the centre from which all variations must be measured. 



Starting from A = 25, the average difference between A and the 

 middle-value Mr, was calculated at — 0.8883, the middle-value thus 

 becoming Mn = 25 — 0.8883 = 24.111. 



For the standard deviation o = 14.4J4 was found. 



1) W. Johannsen, Elemente der exakten Erblichkeitslehre. Deutsche Ausgabe, 

 1909, Drilte Vorlesung. 



