Early Development of the Hen's Egg. 107 



IV. Functions of the Oviduct. 



The whole reproductive apparatus is a most delicately adjusted 

 mechanism. The primary function of its oviducal portion is to 

 transmit the egg from the body cavity to the exterior, but in the 

 course of its evolution it has taken up several other functions, such 

 as transmitting and storing sperms and the secreting of the accessory 

 layers around the egg. The co-ordination between the infundibulum 

 and the ovary is often very exact and delicate, but it is in the birds 

 that we see this co-ordination reaching its highest degree of per- 

 fection. Coste describes the infundibulum as actually embracing 

 the ovum in its follicle at the time of ovulation, and the writer has 

 been able to confirm his statement by several observations. Coste 

 believed that the infundibulum exerted some pressure on the follicle, 

 and it may be that this is the direct cause of ovulation. Indeed, 

 it is highly probable; for while ovulation may take place without 

 the direct assistance of the oviduct, as in the lower vertebrates, yet 

 the weight of evidence supports the opposite view. We have been 

 able to show (in a paper not yet published) that the follicular orien- 

 tation is preserved in the oviduct, and furthermore that this preserva- 

 tion probably occurs only when ovulation is directly caused by the 

 activities of the infundibulum. 



This explanation of ovulation also gives us the key to the solu- 

 tion of another problem, viz., why it is that normally but a single 

 egg is found in the oviduct at a time. If we examine the oviduct 

 of a hen that is laying daily, some time before the deposition of 

 an effS, it will be found to be inactive ; but an examination shortly 

 after laying, reveals the fact that the oviduct is in a state ol high 

 excitability, with the infundibulum usually clasping an ovum in 

 the follicle. In one case it was embracing a follicle containing a 

 half-developed ovum, and with such tenacity that a considerable 

 pull was necessary to disengage it. It seems certain, therefore, that 

 the stimulus which sets off the mechanism for ovulation is not re- 

 ceived until the time of laying, or shortly thereafter. So long as 

 there is an egg in the lower part of the reproductive passage the 

 infundibulum apparently does not clasp the ovum, and a second egg 

 is thus prevented from entering the oviduct. 



