Daddy. P. irus.  Adult eunuch.

Mutt. P. irus.  Young adult male.  Born August, 1911.

Julius. Pongo pygmaeus.  Male.  Age, 4 years to 5 years.

When I arrived in Santa Barbara, Doctor Hamilton was about to remodel, or rather reconstruct, his animal cages and laboratory.  This gave us opportunity to adapt both to the special needs of my experiments.  The laboratory was finally located and built in a grove of live oaks.  From the front it is well shown by figure 10 of plate III, and from the rear, by figure 11.  Its location was in every way satisfactory for my work, and in addition, the spot proved a delightful one in which to spend one’s time.

[Illustration:  FIGURE 12.—­Ground plan of Montecito laboratory and cages.  Scale 1/120

L, laboratory; C, cages; A, experiment room in which multiple-choice apparatus was installed; B, E, additional rooms for research; D, store room and shop; Z, large central cage communicating with the eight smaller cages 1-8.]

Figure 12 is a ground plan, drawn to scale, of the laboratory and the adjoining cages, showing the relations of the several rooms of the laboratory among themselves and to the nine cages.  Although the construction was throughout simple, everything was convenient and so planned as to expedite my experimental work.  The large room A, adjoining the cages, was used exclusively for an experimental study of ideational behavior by means of my recently devised multiple-choice method.  Additional, and supplementary, experiments were conducted in the large cage Z. Room D served as a store-room and work-shop.

The laboratory was forty feet long, twenty-two feet wide, and ten feet to the plate.  Each small cage was six, by six, by twelve feet deep, while the large compartment into which each of the smaller cages opened was twenty-four feet long, ten feet wide, and twelve feet deep.

II

OBSERVATIONAL PROBLEMS AND METHODS

My chief observational task in Montecito was the study of ideational behavior, or of such adaptive behavior in monkeys and apes as corresponds to the ideational behavior of man.  It was my plan to determine, so far as possible in the time at my disposal, the existence or absence of ideas and the role which they play in the solution of problems by monkeys and apes.  I had in mind the behavioristic form of the perennial questions:  Do these animals think, do they reason, and if so, what is the nature of these processes as indicated by the characteristics of their adaptive behavior?