20 INHERITANCE, FERTILITY, AND SEX IN PIGEONS. 



young ones may be reared, and if the weather keeps mild throughout they will in that 

 case make wonderfully strong early birds, still the chances are many against it. But still 

 more though the young be reared, the result is likely to be the ruin of the constitution of 

 the hen ; for if she is what is called a free breeder, or lays her eggs fast, before the season 

 is over she becomes so weak as in many cases to become ruptured, and in other cases barren, 

 when she is of course valueless. The cause of this is not only the excessive laying — indeed 

 a young and rank hen will often lay, like a fowl, whether she be mated or not — but the 

 cock-bird continually driving her to nest and teasing her while in her weak state, which 

 causes her weakness of course to increase, until the ovary gives way, and she becomes what 

 is called "down behind." A most singular fact is that we have often noticed the mate 

 of such a hen to become similarly affected, in which case he is commonly said to be "gizzard- 

 fallen"; but having dissected many birds in such a condition, we can state positively that 

 the gizzard has nothing to do with it, but that the part affected is a portion of the intestines. 

 We never knew a cock breed in such a condition ; and though we have occasionally known 

 a hen do so, the progeny of such birds could not be expected to have any but a weakly 

 constitution. In any case, it is much better to get even only three or four pairs of eggs 

 in a season, hatched at a time when they are likely to become strong and healthy birds 

 and preserve the constitution of the parents also for next season. We have known some 

 persons, by what is called "pumping" a hen, or breeding from her as long as possible, 

 obtain eight or nine pairs of eggs from her in one season ; but we have seldom known more 

 than half reared, and often some of these would have crooked breast-bones, which is a 

 great fault as well as a sign of weakness. And as to the hen herself, she is, as already 

 stated, if not entirely ruined, seriously debilitated for life, so that none of her after progeny 

 will be as vigorous as they ought to be." 



The data of this volume will sho^v that the various species of wild pigeons and 

 many of their hybrids can be overworked, or "pumped," very much more exten- 

 sively than is indicated above for the domestic pigeon breeds, and without such 

 evident permanent somatic injury to the parents. A more complete analysis of 

 the relation of season and the order of the egg of the clutch (in wild sjiecies) to this 

 weakening, and the relation of all of these points to fertility and to sex is, however, 

 treated for the first time in these pages.'-' 



It may be emphasized that Professor Whitman was by no means inclined to 

 dogmatize as to the interpretation of this sex series. The editor had ample oppor- 

 tunity to know the author's mind on this subject better than on most others, since 

 during the winter of 1908-9 it was decided that the present editor should join 

 in an attempt to learn more of the germs which might beforehand be known to be 

 of male-producing or of femalc-i)roducing value. The chemical investigations 

 then outlined and several other investigations in line with the original purpose 

 have been, and are now being, continuously carried on and will be published by 

 the editor probably not long after the present volume leaves the press. We would 

 add here that if the data which the author had before him, and now found in these 

 pages, leaves doubt that a real reversal of sex was effected in the cases herein 

 described, such doubt would seem to be wholly excluded by the results of the four 

 years of additional study of this material by the editor, the studies having been 



12 It seems scarcely necessary to st:itc (li:if Wliilm.'iir^ iicnn ,!i. :,i'.,ii- ii| infiTlility. l.,i,i;,-vil y, dc , were 



made after an accounting of such extorn:il or ini'Mlriii.il ilun^:- :i \' ' •■ •■ .i ' iin, pnui- ircdm^;, |i^"ii .■ m, un .iirr 

 winter mortality (of all birds — the early :iii(l ilic l:itc-li:ii iIm -I ' Mi'ilJ icinl u, umlr i hr Im-I - oi l:iic 



season shorter-lived on the average than tlmse liali-lu'd cailini aimjn^ |ii;;iuii.., i Ic. The very lull data ul llic l.ilju- 

 latcd breeding records amply demonstrate this. — Editok. 



