294 BOAED OF AGRICULTUEE. 



secured at the lowest price ; they were begun with the hen. 

 Two young German physiologists, Pander and D'Alton, 

 under the guidance of Professor Dollinger, began that study, 

 and, in order to ascertain how the chick is formed, — not 

 how the chick grows in the egg, but how it is formed during 

 the first hours after the sitting of the hen upon the egg 

 has begun, — they opened three thousand eggs. Now, why 

 is it that we have not yet such knowledge of the horse? 

 Because there are not three thousand mares to be sacrificed 

 to study their development ; and unless some means are 

 found by which something of the kind can be done, we 

 cannot have the beginning of the history of that one ani- 

 mal ; unless, perhaps, with the greater knowledge we now 

 possess and long acquired skill, a smaller number of indi- 

 viduals may suffice ; but not until hundreds and hundreds of 

 animals are sacrificed for that purpose, under proper condi- 

 tions, can we have the first fact concerning their history. And 

 if you find in physiological text-books this subject treated as 

 if it were entirely known, it is simply because the data in 

 reference to the animals, the physiology of which is given in 

 our text-books, are borrowed from the four animals carefully 

 studied by Bischofi*, and not from any particular knowledge 

 obtained from the domesticated animals themselves. When, 

 in our human physiology the embryology of the human 

 race is presented, it is largely illustrated by conditions which 

 have been studied from the rabbit, the dog, the gu'nea- 

 pig and the roebuck. Direct observations are so few that 

 they are hardly worth mentioning. A few cases of suicide 

 have furnished the only information which is on record con- 

 cerning the first condition of the human being. 



And now I propose to show you what an egg is, and then 

 to satisfy you that all animals produce such parts as deserve 

 the name of egg. 



A hen's egg, surrounded by its shell, which is calcareous, 

 is lined on the interior by a double membrane. A skin ex- 

 tends over the whole internal surface, and that skin is double ; 

 and in one part of the shell it recedes from the shell and 

 leaves an open space, which is the air-chamber of the egg. 

 These are only protections of the egg, and are formed last 

 upon it. In the interior of the egg we have a round ball 



