Margaret Floy Washburn

The book states that it deals throughout with comparative rather than genetic psychology¹. Its bibliography was selective. Where the literature on one point was very large, as with the function of the semicircular canals, Washburn gave only a few of the more important references².

Washburn reported experiments and judged them. On spiders, Dahl found that body hairs responded to violin tones. Washburn called this test, which Hensen had applied to Mysis, of very doubtful significance, and noted that hairs on the human hand would respond too³. For Paramecium, the text lists conditions that change the response to gravity, including food supply, temperature, mechanical shock, salts and alkalies⁴. It also relays a suggestion that downward movement protects the animals from surface agitation, ice and loss of food⁴.

Bayliss pointed readers to the book as an example of investigating the higher nervous functions without necessarily introducing consciousness⁵. In 2015 Lyon described it as the first US textbook on comparative psychology, one that begins with amoeba. Lyon placed it beside Jennings' claim that the behaviour of lower animals, bacteria included, can inform us about higher animals⁶.