5^4 GENERATION. SECT. XXXIX. 4. 



quired organs, which can change thefe firft nutritive 

 particles, as explained in No. 5. 2. of this Section. 

 And as thefe nutritive particles are fuppofed to be 

 fimilar to thofe, which are formed for her own nu- 

 trition, it follows that the fetus fhould fo far refem- 

 ble the mother. 



This explains, why hereditary difeafes may be de- 

 rived either from the male or female parent, as well 

 as the peculiar form of either of their bodies. Some 

 of thefe hereditary difeafes are fimply owing to a 

 deficient activity of a part of the fyftem, as of the 

 abibrbent veifels, which open into the cells or cavi- 

 ties of the body, and thus occalion dropiies. Others 

 are at the fame time owing to an increafe of fenfa- 

 tion, as in fcropbula and confumption ; in thefe the 

 obstruction of the fluids is firft caufed by the inirri- 

 lability of the vefiels, and the inflammation and ul- 

 cers which fucceed, are caufed by the confequent 

 increafe of fenfation in the obftructed part. Other 

 hereditary difeafes, as the epilepfy, and other con- 

 vulfions, confiil in too great voluntary exertions in 

 confequence of difagreeable fenfation in fome parti- 

 cular difeafed part. Mow as the pains, which oc- 

 cafio& thefe convulfions, are owing to defect of the 

 action of the difeafed part, as (hewn in Sect. XXXIV. 

 it is plain, that all thefe hereditary difeafes may have 

 their origin either from defective irritability derived 

 from the father, or from deficiency of the ftimulus 

 of the nutriment derived from the mother. In ei- 

 ther cafe the effect would be fimilar ; as a fcrophu* 

 lous race is frequently produced among the poor 

 from the deficient (limulus of bad diet, or of hun-. 

 ger ; and among the rich, by a deficient irritability 

 from their having beeii long accuftomed to* too 

 great ftimulufl, as of vinous fpirit. 



6. From this account of reproduction it appears, 

 that all animals have a fimilar origin, viz. from a 

 Tingle living filament 5 and that the difference of 



their 



