XXVm INTRODUCTORY OBSERVATIONS, 



tus; that there isfome generative power developed 

 with age, which can produce a germ capable of 

 being fecundated by the male. Difcordant opi- 

 nions like thefe have divided the moft celebrated 

 philofophers ; ingenious arguments have been gi- 

 ven for each ; and if infinite involution is the 

 more generally adopted, perhaps it is becaufe the 

 cxpanfion of parts in miniature is lefs repugnant 

 to the mind than creation. — Yet changes cer- 

 tainly take place in the bodies of animals, which 

 may almofl be called creation. New parts are 

 acquired ; though thefe may be derived from other 

 exifling fubftancies, flill they form a part of the 

 body. The cartilages of a fcEtus undoubtedly do 

 not contain principles exadly the fame as the bones 

 of an adult. Solids may be involved in other fo- 

 lids ; but it was never faid that fluids could be in- 

 volved in fluids. The blood, the milk, the bile, 

 urine, and the numerous other fluids in the human 

 body, mufl be derived from other fubftances, be- 

 caufe the quantity of any one is fo fmall in the 

 fcetus ; not to name that prolific fluid which does 

 not exift before a particular fl:ate at which the 

 body arrives. The folids muft alfo acquire new 

 parts ; increment in fize may be effeded indeed, 

 by expanfion alone, but no additional weight 

 will be gained. — But this is entering on the pro- 

 found theory of increment. Thefe fads bear 

 fome difl:ant refemblance to creation, notwith- 

 ilanding they are ojily the aflimilation of one fub- 



flance 



