I was saddened to read in the Spring 2018 issue of Ken Christiansen’s death and his wife’s not long afterwards [“In Memoriam,” Page 46]. I took biology from Mr. Christiansen when I was at Grinnell — I graduated in 1959. The classroom was one of those large rooms with banked seats for students. I loved the class, though I was an English and American lit major. What I remember most vividly was that during one of Mr. Christiansen’s lectures, a small squirrel climbed up out of his pocket, where it apparently spent the day, scrambled up the front of his jacket and onto his shoulder, where it peed. Mr. Christiansen smiled and went on with his lecture. What a man!