13 Y D. EMBLETOX; M.D. 73 



end of the egg which is most convenient shall be the first to come 

 into the world. 



But it is known that in human parturition the rule is, that 

 the large or head end of the ovum presents itself and passes first, 

 for when this is once extruded no further difficulty remains. 

 This therefore is the most convenient end to be born first. The 

 rule, of course, has its exceptions, the small or foot end at times 

 presenting itself, not to mention various forms of cross birth. 



The same rule and exceptions occur in the case of the lower 

 Mammalia. 



It is also well known, that on the passage of the mammalian 

 ovum, a copious secretion from the walls of the uterus, etc., occurs, 

 and more or less effusion of blood takes place, which might and 

 would impart most colour to the broad presenting end, and in a 

 lesser degree to the rest of the ovum as it passes out, were the 

 mammalian ovum constituted like that of the bird. 



From analogy, therefore, we may believe that mutatis mutandis 

 very similar occurrences may take place, as in fact they do, 

 during the laying of an avian ovum. 



In civilized human communities births that are abnormal, that 

 is, not according to the generally prevalent law, are, it is believed, 

 more frequent than among uncivilized races who lead simple 

 lives ; and therefore it is not improbable that the same difference 

 obtains among highly domesticated fowls, so that we might ex- 

 pect to find more abnormal births of eggs among them than among 

 wild birds. 



Granting for the jnTscnt that the marks on birds' eggs arc 

 caused by escapes of blood from the lining membrane of the ovi- 

 duct, it might fairly be expected that these marks would be more 

 numerous, larger, and more highly coloured, on that end of the 

 egg which is the first to come down, and especially if that were 

 the larger end ; for this would offer greater impediment at once, 

 and would require a greater exertion of muscular energy for its 

 propulsion, whilst its extended and roughened surface would hv 

 most likely to cause abrasion or rui)ture of blood vessels. If the 

 small end presented itself first it might also cause abrasion, rup- 

 ture, and escape of blood, but these woukl be less tlian in the 



