METAMORPHOSES OF ANIMALS. 



101 



prchensive, that all subsequent researches in this depart- 

 ment of our science may be considered as only a further 

 development of the facts first noticed by him, and of the 

 results he has already deduced from them. 1 It was he 

 who laid the foundation for the most extensive generali- 

 zations respecting the mode of formation of animals ; for 

 he first discovered, in 1827, the ovarian egg of Mam- 

 malia, and thus showed, for the first time, that there is no 

 essential difference in the mode of reproduction of the 

 so-called viviparous and oviparous animals, and that man 

 himself is developed in the same manner as animals. 

 The universal presence of eggs in all animals, and the unity 

 of their structure, which was soon afterwards fully ascer- 

 tained, constitute, in my opinion, the greatest discovery 

 in the natural sciences of modern times. 2 



1 Without referring to the works 

 of older writers, such as De Graaf, 

 Malpighi,Ilaller,Wolf,Meckel,Tiede- 

 mann, etc., which are all enumerated 

 with many others in BISCHOFF'S arti- 

 cle, " Eutwickelungsgeschichte," in 

 WAGNER'S Handworterbuch der Phy- 

 siologic, vol. i, p. 860, I shall men- 

 tion hereafter, chiefly those published 

 since, under the influence of Dollin- 

 ger, this branch of science has as- 

 sumed a new character : BAER (C. 

 E.v.),TJeberEntwickelungsgeschichte 

 der Thiere; Konigsberg, 1828-37, 2 

 vols. 4to., fig. The most important 

 work yet published. The preface is 

 a model of candour and truthfulness, 

 and sets the merits of Dollinger in a 

 true and beautiful light. As text- 

 books, I would quote, BURDACH (C. 

 F.), Die Physiologic als Erfahrungs- 

 wissenschaft ; Leipzig, 1829-40, 6 

 vols. 8vo.; French, Paris, 1837-41, 9 

 vols. Svo. MULLER (J.), Handbuch 

 der Physiologic des Menschen ; Cob- 

 lenz, 1843, 2 vols. Svo., 4th edit.; 

 Engl., by W. BAYLY, London, 1837, 

 8vo. WAGNER (R.), Lehrbuch der 

 Physiologic ; Leipzig, 1839-42, 2 vols. 



Svo. VALENTIN (G.), Handbuch der 

 Entwickelungsgeschichte, etc. ; Ber- 

 lin, 1835, 1 vol. Svo. Lehrbuch der 

 Physiologic des Menschen ; Braun- 

 schweig, 1843, 2 vols. 8vo. LONGET 

 (F. A.),Traite de Physiologic; Paris, 

 1850, 2 vols. Svo. KOLLIKER (ALB.), 

 Microscopische Anatomic des Men- 

 schen ; Leipzig, 1840-54, 2 vols. Svo. 

 fig. See also OWEN'S Lectures, etc., 

 SIEBOLD und STANNIUS'S Lehrbuch, 

 and CARUS'S Morphologic, q. a., p. 37 

 and p. 24. I might further quote 

 almost every modern text-book on 

 physiology ; but most of them are so 

 evidently mere compilations, exhibit- 

 ing no acquaintance with the sub- 

 ject, that I purposely omit to men- 

 tion any other elementary works. 



3 BAER (C. E. a.), De Ovi Marnma- 

 lium et Hominis Genesi ; Konigsberg, 

 1827, 4to., fig. PURKINJE (J. E.), 

 Symbols ad Ovi aviura historian! 

 ante incubationem ; Lipsise, 1830, 

 4to., fig. WAGNER (R.), Prodromus 

 Historic generationis Hominis atque 

 Animalium, etc.; Lipsiso, 1836, 1 vol. 

 fol., fig. Icones physiologicse ; Lip- 

 sis3, 1839, 4to., fig. Compare also 



