198 EDWARD HORNE CRAIGIE 
The accompanying illustrations (fig. 1) show these areas with 
the points where the measurements of vascularity were made 
indicated approximately by the hatched spaces. The outlines 
of the cortical regions are based upon a comparison of Sugita’s 
reproduction of Fortuyn’s figures with the former author’s own 
illustrations of sections, and his correlation of both these with 
Brodmann’s terminology. The outline of the brain was taken 
in the first place from two injected specimens which had been 
carried only as far as the 70 per cent alcohol stage in preparation. 
The laminae of the cortex were by no means easily distin- 
guished in many cases, the simple picric-acid stain which was 
employed not being well adapted for such a purpose. By careful 
comparison, however, with a series of sections stained with 
toluidine blue and erythrosin and with the specimens in which 
the layers were more distinct, they were located fairly accurately, 
it is believed, even in the more difficult cases. 
Figure 2 shows the cell lamination and the vascular supply 
in the occipital cortex of one rat. 
OBSERVATIONS 
The measurements obtained are presented in table 1. The 
results for the eight brains have been averaged and the probable 
error of the averages calculated, these figures being given at the 
right-hand side of the table. The probability of error tends, 
of course, to be a little higher than was the case in the previous 
study on account of the use of only eight brains instead of ten. 
The ratios of the averages to the readings for the ventral white 
funiculus and the ventral gray cornu of the spinal cord in the 
same individuals! are given in the last columns of table 3. The 
sex of each rat has been indicated in table 1 by placing M. or 
F. in front of its identification number, while its locality is 
shown by adding ‘Toronto’ or ‘W. I.’ (The Wistar Institute). 
In the preparation of the tables the mean values for the five 
laminae in each area, as shown in table 1, were averaged, and 
the areas were arranged in order of increasing vascularity, as 
thus determined. These averages are recorded in table 2. The 
1 See Craigie (’20). 
