15 



biology. But it must be borne in mind that the older 

 zoologists, having no microscopes, were not acquainted with 

 the complex structure of the creature ; and further, that the 

 conception of evolution itself had not been evolved, and 

 consequently exercised no control over any theories or 

 hypotheses which might be advanced. 



From Aristotle to Harvey. 



As early as the 4th century B.C., ARISTOTLE, in his " History 

 of Animals/' stated that " the Ascarides 1 "the name given 

 to the threadworm by the Greeks " spring from the human 

 excrements 2 " ; and until the 17th century A.D., all naturalists 

 subscribed to his opinion, without question 3 . To WILLIAM 

 HARVEY, the discoverer of the circulation of the blood, is 

 due the credit of having given the death-blow to the theory 

 of " spontaneous generation " by his celebrated maxim : Omne 

 vivum ex ovo. This phrase, literally " every living thing 

 comes from an egg " really means : Xo living thing can come 

 into being except by direct descent from another individual 

 of the same or of a very similar kind ; a doctrine which was 

 destined to have the most far-reaching effects on the whole 

 science of biology. 



The Second Phase: 



The second phase was much shorter, lasting from the 17th 

 century down to the second decade of the 19th, when BREMSER 

 published the results of his researches. During this period, 



1 The origin of the name is TOLS 6015, olov at KaXov/n evat e\/j.iv6es. 

 graphically explained by JOR- e a-Ttd'auTuv 761/77 rpia, ! tjr'ovo]Li.a^ofj.evrj 

 DENS : " Der von iricapt^riv TrAareTa, /ecu at (TTpoyyi\ai. Kal TpiVcu 

 (springen, tanzen), hergenommene cu ctovcopiSes, eV yuei/ ov rovr<av erepov 

 Geschlechtsname aaxapiSfs passt ov8ev yiyvercu." (AmSTOTELis De 

 vorziiglich auf diese Gattung, animalibus historia, Textum recog- 

 welche iiberaus unruhig and leb- novit L. DITTMAYER, Lipsiae, 1907, 

 haft in ihren Bewegungen sind p. 187.) 



und, wenn man ihnen ein Licht 3 The following is a gem of medi- 



vorhalt, wohl einige Zoll weit cal dialectics on this point : 



springen." (JORDENS, D. J. H., " Vermes in eo loco generantur, 



Entomologie und H elminthologie in quo excrementa colliguntur, 



des menschlichen Koerpers, Hof, minime in loco ubi fit concoctio. 



1802, vol. ii., p. 20.) At excrementa colliguntur in in- 



2 In this much-quoted passage, testinis ; concoctio fit in ven- 

 Aristotle says: "...TO S'eV 6ptl triculo. Ergo in intestinis gene- 

 Cvcav, TO. 8' eV (rapid TU>V ^wv, ra 8' rantur, non in ventriculo." (CAM- 

 fvra"iS Trepirrw/uLaai, Kal TOVTUV ra fj.fv POLONGUS, ^EMIL., Tractatus de 

 e'/c /cexcopifTyueVcov, TCI 8' eVt UVTMV eV i^ermibus, Paris, 1634, cap. II.) 



