As the problems always took me longer than they did her I never checked them at the time, but went over them later, after she had given all her answers. I did this moreover, so that she should have no opportunity of tapping my thoughts and thus rely on me; indeed, I really _forced_ her to do her own thinking. For even if I did begin to calculate I did it so slowly, that she was rapping out her reply long before I was done. I say all this to my own shame, for Lola must have her due--and I never had a head for arithmetic myself! When she knew how to calculate time, I put the following question to her: "How many minutes are there in an hour and a half--less thirty minutes?" Answer: "60." "How many hours are there in 240 minutes?" Answer: "4." By this time Lola had also learnt the value of money. About the end of April, 1916, she could distinguish between such coins as 5 Pfennige, 10 Pfennige, 50 Pfennige; 1 Mark, 2 Mark, and 5 Mark, and could compute the value of the Mark in Pfennige. When showing my friends what she could do in the way of arithmetic, her money sums were a special feature and delighted everybody. Here is an example, the date being 31 May: I put the question: "12 Mark less 4 Mark 10 Pfennige?" adding--"Tell me the Mark!" Answer: "7." "And the Pfennige?" "90" (i.e. 7 Mark 90 Pfennige.) Question: "What coins do you know?" Answer: "5, 10, 50; 1, 2." "And what are they all?" "Fenig." (i.e. Lola's mode of spelling Pfennig.) "Lola, how much of a Mark are 50 Pfennige? The answer has to do with fractions." Answer: "1/2." "How much are 225 Pfennige?" "2-1/4." "And 20 Pfennige?" "1/5." "And 60?" "3/5." "And 3/20 Mark, how many Pfennige?" "20." _"No!_ "8/20 Mark?" Answer: "15." Towards the close of 1916 I taught her to raise numbers to various powers. At this she was slow in the beginning, but ultimately mastered it fairly well. She could soon answer such questions as--"3^3 = ?" with "27." And--"4^2 = ?" with "16," doing so, moreover, with ease; but up to now I have not been able to take her any further in the matter of extracting roots; in the first place I have had little time to give to it, and secondly, I am by no means on very sure ground there myself! I might, of course, have rubbed up my own rusty arithmetic had my interest in this particular accomplishment of Lola's been greater. But--for my own part, I attach greater importance to the psychological side of this question, and would far rather probe and delve within the depths of her dog-soul, exploring the extent of her other abilities, since arithmetic has already some brilliant exponents in, for instance, Krall's horses. WORKING WITH OTHER PERSONS.