276 THE NA TURE-STUD Y RE VIE W [ 2 : 8-nov., 1906 



explanation is more probable. It is significant in this connection that 

 the secondary maximum for the men falls to the left of the primary 

 maximum, thus indicating a less degree of knowledge, while for the 

 women the conditions are reversed, the primary maximum falling in 

 the column of less and the secondary maximum in that of greater 

 knowledge. The interpretation is tentatively advanced that these 

 double maxima indicate the existence among both men and women of 

 two somewhat distinct groups, — an '-out-door" group and an "in- 

 door" group, the first large in the case of men, the second in the case 

 of women. It is tempting to correlate these groups with country and 

 city life; but the proportion of city and country students is presumably 

 about the same for the two sexes. More likely the distinction is one 

 of temperament and taste, the large "out-door" group of men result- 

 ing from the generally more active life of men, already noted as 

 reflected in Table 1. In exaggerated statement, the secondary 

 maxima maybe said to be determined respectively by the "torn -boys" 

 and the "sissies." 



The isolated fragment of solid line at the extreme right (I and III) 

 represents a single student, — a farm boy, self-trained in accurate 

 observation of nature, and later an excellent assistant in the work of 

 the course. 



The curves for the close of the course (broken lines) are less regu- 

 lar; but again the curve for the whole class (III) shows clearly its 

 composite nature, the two well marked apices corresponding respec- 

 tively to the maxima for men and women (L and II). 



A comparison of the broken with the solid lines in Table 2 gives a 

 fair impression of the gain in knowledge during the course: but this 

 is more strikingly brought out by the figures of Table 3. From these 

 it may be seen that the average number of birds known has increased 

 107 per cent, for the men, 165 per cent, for the women, and 138 per 

 cent, for the entire class. It is fair to add, also, that the knowledge 

 claimed at the close of the course is subject to much less discount 

 for error than that at the beginning. 



Table 3 



Men and Women Men Women 



Minimum at beginning of course .. 4 10 4 



Minimum at close of course 22 25 22 



Maximum at beginning of course 75 75 40 



Maximum at close of course 75 75 7° 



Average at beginning of course 21 27 17 



Average at close of course 50 56 45 



Number of species of birds* known by individual students. Data refer only to species 

 listed in Table I. 



