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XII. — An account of the Dissection of a Human Embryo of about the 

 Fourth Week of Gestation, with some Observations on the Early 

 Development of the Human Heart. By Arthur Farre, M.D., 

 F.K.S., Professor of Midwifery in King's College, &c. 



(Read March 19th, 1850.) 



There is, perhaps, no department of physiology, which so much 

 needs a careful and accurate record of the various facts and ob- 

 servations which time and opportunity afford, as that relating to 

 human embryology. Numerous as have been the investigations 

 carried on of late years into the wonderful and complex processes of 

 reproduction, there is still no one stage of it which can be said to be 

 yet thoroughly explored; and certainly in no case is the path of 

 observation beset with greater difficulties, than in the effort to carry 

 out a connected series of observations on the early development of 

 the human frame. 



The causes of this difficulty in regard to man, as compared with 

 other animals, are so obvious, that to enter upon a consideration of 

 them here would be quite superfluous. But I may observe that in- 

 dependent of the comparative rarity of the opportunities afforded, 

 and the impossibility of learning from experiment in the human 

 subject, while in animals our occasions may be as numerous and di- 

 versified as we choose to make them ; there are added in our own 

 species these further difficulties, that the ova or embryos discharged 

 in abortion are most frequently malformed (malformation being a 

 very common cause of abortion) ; that even the comparatively few 

 specimens which are not malformed, are still generally broken and 

 destroyed by the action of the uterus on their tender structure, 

 during the process of expulsion ; while, lastly, if the specimen has 

 escaped this ordeal, it is too often injured by the rough handling of 

 curious observers before it comes into our hands. 



I trust, therefore, the Society will partake in the interest which I 

 feel, in having just now one of these opportunities of examining the 

 conformation of the human embryo, at almost the earliest period at 

 which the microscope can be employed in the investigation of its 



TRANS. MIC. SOC. VOL. III. K 



