148 BOARD OF AGRICULTURE. 



in the production of individual animals so laid out before a 

 mind capable of investigating the process, and which could so 

 estimate their various values as to project them in a mechani- 

 cal form, a figure could be drawn in which the resultants of 

 the forces could be represented by a line, which would inva- 

 riably indicate the value of the concrete forces which would 

 be the contribution of the parties to reproduction. This is 

 to say that certainty of result would follow complete and 

 exact knowledge, and the corollary is equally obvious, that 

 when we have uncertainty in practice, it can be explained by 

 the deficiency of our knowledge. 



To demand this complete knowledge is to demand a mind 

 which is infinite to our present conceptions ; but it is in our 

 power to continuously encroach upon the borders of our igno- 

 rance, and, while extending the boundaries of our knowledge, 

 gain increased control over the forces of nature. 



The study of physics, or philosophy applied to nature, to 

 me, at least, indicates the possibility of "spontaneous* gen- 

 eration." But as this doctrine, so reasonable in itself, is the 

 subject of so much prejudice, and not as yet satisfactorily 

 demonstrated, we may at present claim that life is always 

 derived from preexisting life. The terms which we apply to 

 this derivative process are reproduction and generation. The 

 word reproduction is general in its meaning, and includes the 

 history of the changes which take place in the organs and 

 functions of the individual, by means of which new matter is 

 formed, as well as the production, growth and development 

 of the new germs which make their appearance through gen- 

 eration. The word generation, strictly speaking, has refer- 

 ence only to the changes immediately following the act of 

 begetting, but usually includes somewhat of the past history 

 of the separate cells which take part in this process, as well 

 as some history of the development of the new life thus 

 formed. The generative process appears to consist essen- 

 tially in the union of the contents of two cells, or the differ- 

 entiated product of one cell, by which the germ of what may 



* Spontaneous : I use the word in the sense of produced without any special cause 

 or method being assigned, as of the appearances of life without any evidence of its 

 being produced from an existing vitality, — that is, the convertibility of forces. To 

 use the word as if it involved the production of life without cause, or not in accord- 

 ance with law, would involve an absurdity of thought. 



