A BIOLOGICAL FARM. 2 I/ 



development of instinctive behavior, and even in voice-changes 

 and food-instincts at certain life-epochs corresponding seemingly 

 to evolution-epochs. Remembering that the distant ancestors 

 of land animals were undoubtedly aquatic, the history of in. 

 dividual development in amphibious forms of to-day becomes 

 intelligible as an abbreviated and variously modified record of 

 race development. Making all allowance for secondary adaptive 

 changes, it is nevertheless safe to say that race evolution is 

 sketched in the development of the individual sketched not only 

 in fundamental features of structure, but also in the accompanying 

 physiological and psychological changes. 



Reminiscences of aquatic life are seen not only in land animals 

 that return to the water to deposit their eggs, but also in all the 

 higher animals, since they begin life in the unicellular stage and 

 require for their first development to be bathed in fluid. 



Sequence in color-patterns, so characteristic of young animals 

 of almost all species, and especially so of birds, furnishes in- 

 numerable illustrations of the biogenetic law, and in many cases, 

 where-only two extremes of the sequence are present, it is possi- 

 ble by simple experiment to bridge the gap, and thus to show 

 that the two extremes are really two stages of a continuous 

 development. For example, in some wild species of pigeons we 

 find that the color-pattern of the first plumage succeeding the 

 down is so different from that of the second (adult) plumagt, as 

 to appear to have no direct developmental relation to it. By 

 plucking one or more feathers from the first plumage at differen 

 times before the first moult, intermediate stages can be obtained, 

 showing precisely how the first pattern can be progressively con- 

 verted into the second. Such experiments enable us to force 

 from nature more complete records of her past and present doings- 



Work on living organisms, dealing with such subjects as 

 heredity, variation, adaptation, correlation, development, re- 

 capitulation, hybridisation, origin of species, nature of specific 

 characters, life-histories, habits, instincts, intelligence, etc., re- 

 quiring uninterrupted continuance from year to year for long 

 periods, under conditions that secure most favorable control for 

 experimentation and study, calls for facilities which have yet to be 

 provided. 



