42 CARNEGIE INSTITUTION OF WASHINGTON. 



Now, if it were only possible to get at these representative par- 

 ticles within the egg, what changes might not be effected in the de- 

 velopment of the bird ! To take a very simple example, the peacock 

 has a white variety, lacking the bright colors of the feathers. If in 

 the egg of an ordinary peacock we could seize upon the representa- 

 tive particles of the color and impede their development, perhaps 

 we would succeed in reproducing the white variety at once and 

 quite artificially. 



Obviously this is the heart of the matter, for if once the principle 

 should be discovered to dislocate such a representative, we might 

 apply it to numerous other instances. A white peacock would be 

 no novelty and no gain, but we would be able to make white varie- 

 ties of other birds and other animals, and perhaps even of the bright- 

 colored flowers, which until now have resisted all endeavors of the 

 breeders in this line of work. 



The white-color varieties are, of course, only intended as an 

 example. Other and more valuable qualities might likewise be 

 expected to become changeable. There would be no limit of suc- 

 cess if that principle were found, and why should it not be possible 

 to discover it ? Methods of attacking this question are not at all 

 failing. We might try to kill some of the representative particles 

 in the egg, or to stun them, or to injure them in ever so slight a 

 measure, so as only to retard their development. More than one 

 starting point for such an attempt is at hand. Engelmann has 

 taught us a method of lighting and heating small parts of a living 

 cell. He uses the focal point of a glass lens, which he directs upon 

 the cell while lying under the microscope. If now a very small 

 part is overheated and thereby killed, the remainder of the cell is 

 seen to be still living and apparently uninjured. By refining this 

 method some of the most sensible representative particles might 

 perhaps be killed without too much injury to the others. 



Johannsen has of late discovered that plants may be stimulated 

 by a treatment with narcotizing substances, such as ether and chlo- 

 roform. Dormant buds may be awakened and display their leaves 

 and blossoms even in midwinter. The studies of Overton have 

 thrown considerable light upon the agency of such narcotizing sub- 

 stances upon the living protoplasm. Wilson has proved that visible 

 changes may be effected in the eggs by means of ether. Though 

 these observations seem to justify a hope of success, very much re- 

 mains to be done. If we assume that some representative particles 



