110 WISCOlSrSIN' ACADEMY SCIENCES. ARTS, AND LETTERS. 



THE LAW OF EMBRYONIC DEVELOPMENT— THE SAME 

 IN PLANTS AS IN ANIMALS. 



BY I. A. LAPHAM. LL.D. 



It is now generally admitted that there is a law in the animal 

 kingdom, that the young or embryonic state of the higher orders, 

 of animals resemble the full grown animals of the lower orders. 



As elxamples of this law we have the tadpole, which is a young 

 frog with gills and a tail, resembling the fishes which stand lower 

 in the scale than the reptiles; and the caterpillar, which has the 

 characteristics of a worm, but which is the immature state of the 

 higher class butterflies. 



The discovery of this important law, and its application to par- 

 ticular cases, has been one of the causes of the recent rapid pro- 

 gress in the study of the animal kingdom; it has enabled natural- 

 ists to determine the proper place of certain species in the grand 

 scale of beings, and thus to correct their systems of classification; 

 it has enabled geologists to decide upon the relative age of rocks in 

 some otherwise doubtful cases. It lias also given occasion for much 

 speculation, which m;iy have its use in directing the attention of 

 men to the wonderous works of the Creator. 



It is the purpose of this letter to show, as briefly as possible, that 

 the same law of resemblance between the immature of one order 

 and the mature of a lower order of animals, is equally true in the 

 vegetable kingdom, where its study may Hereafter lead to results of 

 equal importance. 



To understand what follows it will be necessary to recall certain 

 facts respecting the growth, development, organs, etc., of plants of 

 the higher orders. 



They grow from seed planted in the ground, have roots, stem, 

 branches, leaves; they produce flowers with calyx and corolla, and 

 the more essential organs — stamens and pistils; they bear fruit witb 

 seed after their kind, which, when planted, swell and become other 

 plants. 



