810 DR. HANS GADOW ON OVARIES 



referable to tlie inconvenience that might be caused were each 

 oviduct to contain an egg ready to be deposited." Mr. Gunn * 

 takes a reporter's liberty by substituting for " inconvenience " 

 various gruesome calamities, as fracture of the egg-shell, rupture 

 of the oviduct, and even peritonitis ! After thus having tried to 

 throw ridicule upon my generally accepted notion, he assures us 

 that such evil sequences need not be assumed at all because 

 of "the frequency with which Falconidje are found with paired 

 ovaries, which are obviously functional." Then he proceeds to 

 distinguish between several theoretical possibilities besides the 

 only actual condition, namely, that in which the functional organs 

 are those of the left side. 



Not a single case is known of a completely developed right 

 duct, whilst the left is vestigial. Further, I withdraw the state- 

 ment made in the * Dictionary of Birds,' thab " but with rare 

 exceptions only that [ovaryj on the left side becomes functional." 

 " Functional,"' I regret to say, was there used in a loose way, 

 since the I'ight ovary not unfrequently forms rather large eggs. 

 But strictly it should be called functional only if any of those 

 eggs ever became ripe, i. e. burst from the ovary. We know 

 that even relatively large ovarial eggs, even those of the left 

 side, can undei'go complete reduction t. 



Mr. Gunn, however, taking for granted that growing eggs in 

 both ovaries mean that both are functional, and that, although 

 two ovaries may not be a necessity, they must be better than one 

 (a principle which has produced the dou^ble-barrelled gun), has to 

 face the question whether one oviduct can serve two ovaries. 

 We are told that " there is not much evidence for or against tliis 

 supposition," and that " there seems no physical objection to the 

 open end of the tube swinging across the mid-line of the spine, 

 and grasping the right ovvim of the opposite ovary with nearly 

 the same facility as the ovum of its own side." One physical 

 objection to this amazing trick-performance may be the gut with 

 its loops and mesenteries, and it is at least doubtful whether the 

 agile tube (the infundibulum of which is most carefully anchored 

 opposite its own ovary) can overcome these obstacles, in spite of 

 the best-intentioned regulating nerve-stimulus. 



Let us enquire further into the meaning of the one-sided 

 reditction of the female bird's reproductive organs. 



Gegenbaur J favours the size of the egg, the complete egg with 

 albumen and shell, as the primary cause : — " Bei den Vogeln 

 gelangt nur das linke Ovar zu seiner volligen Ausbildung dh. nur 



* T. E. Gunn.— "On the Ovaries in certain British Birds," P. Z. S. 1912, p. 63. 

 Mr. Gunii and tlie Rev. F. C. R. Jourdain credit the late Prof. Newton with the 

 authorship of the article " Reproiluctive Organs " in the ' Dictionary of Birds,' and 

 they suggest as his "German source" of original information Taschenberg's Intro- 

 duction to Naumann's 'Naturgeschichte,' re-edited in 1905, eleven years afier the 

 ' Dictionary of Birds.' 



t Cf. A. von Brunn : " Die Riickbildung nicht ausgestossener Eierstockseier bei 

 Vogeln." Beitrage zur Anatomie und Embryologie, als Festgabe fiir Jakob Henle. 

 Bonn, 1882. 



X Vergleichende Anatomic der Wirbelthiere, ii. 1901, p. 503. 



