124 BOARD OF AGRICULTURE. 



sion, successive fecundation must intervene, because of the pre- 

 cise position in which the egg is fecundated, and the different 

 places in the organs in which they grow to their final condition. 

 Now, in the case of the mammalia, we know so much by the 

 experiments of Bischoff, and I know thus far from actual obser- 

 vation in rabbits and dogs. No experiments on that point have 

 been made upon the cow or upon the mare, so that everything 

 you would like to know with reference to fixing the time when 

 you must copulate, in order to obtain fecundation is to be 

 learned, there is nothing upon record. But about dogs and 

 rabbits, and particularly dogs, this much is ascertained, that 

 what we call heat is the beginning of the natural efforts of the 

 system to throw off eggs from the ovary, before they are fecun- 

 dated, and to set them going in the channel of the sexual organs, 

 downward to the place where they can be fecundated. Now, 

 Bischoff has ascertained that it takes so many hours in a dog 

 for that egg to come down to the point where the sperm will 

 reach it, and fecundate it. He has ascertained, also, that that 

 fecundation does not take place always at the same spot, but 

 that it may take place before the egg has got so far down as the 

 spot where it remains in the womb, to be there attached, form 

 its placenta, and grow. It will perhaps be worth while, in the 

 course of time, to slaughter a number of cows, just at the time 

 they begin to be in heat, to trace the position of the egg while 

 in the downward course, in order to ascertain when it would be 

 best to bring the cow to the bull, in order to obtain fecundation. 

 All these matters bear so directly upon the question of the pro- 

 duction of male and female, that they may be of vital importance 

 in certain districts. But how this question is to be settled, I do 

 not know, because, as I tell you, we have no* book observations 

 respecting the descent of those eggs. The experiments are very 

 difficult. The egg of any mammal is so very small that it is 

 hardly visible to the naked eye. When my eyes were in their 

 best working condition, I could just barely see the rabbit eggs ; 

 but generally, to make sure that I did not mistake a speck of 

 decomposed fat, or some coagulation of blood, for an egg, I had 

 to resort to a magnifier. But even with a magnifier that does 

 not increase more than ten times the diameter, you can see an 

 egg so distinctly that you distinguish its internal organization, 

 and know it is an egg ; so that you can locate the place where 



