1/8 GEOLOGICAL BIOLOGY. 



Such are the steps of the growth and development of the 

 individual by which it passes from a condition of homogene- 

 ous protoplasm to the elaborate organization of the highest 

 animal. 



Are the Laws of Ontogenesis the Same as those of Phylogenesis ? 

 — If we are right in stating that this increasing of the heter- 

 ogeneity is an essential and fundamental law of organism, 

 does it follow that it is also an essential and fundamental 

 law in the processes of phylogenesis, or evolution of species? 



The Meaning of Function.— Before answering this question it 

 is necessary to consider that the use of the term function, as 

 applied to an organ or part of an organism, is quite analogous 

 to the use of the term property as applied to a chemical or 

 physical substance. The mineral loses its crystalline proper- 

 ties when it is melted and the morphological arrangement of 

 its particles is destroyed, although it is the same matter as 

 before, and for the reason that the crystalline properties con- 

 sist in the morphological arrangement of the molecules, not in 

 their chemical composition : so the animal has lost its proper 

 organic function when the physiological processes cease to 

 operate, although the morphological form and constitution of 

 the organic structure still remain. As the crystalline proper- 

 ties are the peculiar marks of the mineral, so the physiological 

 functions are the peculiar marks of the organism, and, teleo- 

 logically, the structure of the organism is built up for the 

 purpose of these functions. The question thus arises: In case 

 there are hindrances to the accomplishment of the functions 

 of any organism as it develops, is it not according to analogy 

 in the other fields of nature to expect the organ to adjust 

 itself to the hindrances to the extent of the capacity of the 

 organism to vary its form? 



A mineral in crystallizing arranges its particles so that, left 

 free to express its characteristics, a particular crystalline form 

 will appear. If a physical obstruction appears in its way, this 

 form will be imperfect, but the law of crystallization is ex- 

 pressed as far as possible ; the whole process of crystallization 

 does not cease because of the hindrance to its perfect action. 

 If we consider function to exist prior to, and to be the 

 raisoii d' ctre of organization, it is to be expected that func- 



