CONTRIBUTIONS TO THE HISTORY 



OF THE BIRD'S EGG PREVIOUS 



TO INCUBATION 



[ I" ] ' PREFACE 



M 



■Y LITTLE DISSERTATION Oil the development of the bird's egg before 

 incubation was submitted five years ago when the medical fac- 

 ulty of Breslau offered felicitations to Blumenbach who was celebrat- 

 ing his fiftieth anniversary under the happiest auspices. It was not 

 publicly printed at that time and came into the hands of only a few. 

 Nevertheless, because of the novelty and importance of the material 

 it was very kindly received by many whom you would readily include 

 among the most celebrated men in the world of letters, indeed it has 

 even brought forth fruit which appears to be more significant than the 

 original material" (see C. E. von Baer: De Ovi Mammalium et Hom- 

 inis Genesi [1827]).'" At the request of many scholars we have under- 

 taken to revise it making only a few slight changes and adding notes; 

 there are certainly not as many such as might be desirable because we 

 are doing other things at present. It is to be hoped that when this en- 

 [^ i\' '2 larged work comes into the hands of a larger number of investigators 

 of natural history some of them will perhaps be stimulated to pene- 

 trate deeper into the subject we have opened up or to develop it 

 further. We particularly urge an investigation of the sudden dis- 

 appearance of the germinal vesicle at the time when the ovarian egg 

 is taken up by the infundibulum. Other problems arise spontaneously 

 before the diligent student. In conclusion may these few pages be 

 again dedicated to Blumenbach, certainly the Nestor among students 

 of nature, now that the fifth year after his anniversary is ending with 

 favorable omens. Breslau, May 301)1. 1 830. 



CO §1 



A more detailed inquiry into the 



cicatricula of the ovarian egg; the 



detection of its vesicle. 



While I was diligently hunting for the earliest primordium of the 

 developing chick, the trail led finally to the cicatricula of the ovarian 



" Numbers in margin enclosed in brackets intlitate page niniibcrs of original. 



" Purkinje's footnotes are left as in the original at the bottom of the page. Superior 

 figures enclosed in parentheses indicate the translator's notes. Occasional words 

 added for the sake of clarity in the translation are enclosed in brackets, as are words 

 of the original which have been inserted here and there. 



