288 RAYMOND PEARL 



5. Well marked broodiness behavior may in certain cases 

 disappear very quickly. 



6. The manifestations of the brooding instinct are apparently 

 closely connected with the functional activity of the ovary, 

 though the precise nature of the connection has not yet been 

 analyzed. 



LITERATURE CITED 



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1880. Veterinarian, Vol. LIII-Vol. XXVI, Fourth Series, p. 331. 



2. Gerhartz, H. Ueber die zum Aufbau der Eizelle notwendige Energie (Trans- 



1914. formationsenergie). Pjluger's Arch. Bd. 156, pp. 1-224. 



3. Herrick, F. H. Analysis of the Cyclical Instincts of Birds. Science, N. S., 



1907. Vol. XXV, pp. 725-726. 



4. Herrick, F. H. The Blending and Overlap of Instincts. Science, N. S., Vol. 



1907. XXV, pp. 781-782. 



5. Pearl, R. On the Accuracy of Trap Nest Records. Ann. Rept. Me. Agr. 



1911. Expt. Stat, for 1911, pp. 186-193. 



6. Pearl, R. The Mode of Inheritance of Fecundity in the Domestic Fowl. 



1912. Jour. Exper. Zool, Vol. 13, pp. 153-268. 



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 1909. Biol. Bui, Vol. 17, pp. 271-287. 



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1909. Birds for Surgical Experiments. Jour. Amer. Med. Assoc, Vol. 52, 

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9. Tegetmeier, W. B. The Poultry Book. London. 



1867. 



