The Period of Von Baer
What Johannes Müller was for physiology, von Baer was for embryology; all subsequent growth was influenced by his investigations.
The greatest classic in embryology is his Development of Animals (Entwicklungsgeschichte der Tiere—Beobachtung und Reflexion), the first part of which was published in 1828, and the work on the second part completed in 1834, although it was not published till 1837. This second part was never finished according to the plan of Von Baer, but was issued by his publisher, after vainly waiting for the finished manuscript. The final portion, which Von Baer had withheld, in order to perfect in some particulars, was published in 1888, after his death, but in the form in which he left it in 1834.
The observations for the first part began in 1819, after he had received a copy of Pander's researches, and covered a period of seven years of close devotion to the subject; and the observations for the last part were carried on at intervals for several years.
It is significant of the character of his Reflexionen that, although published before the announcement of the cell-theory, and before the acceptance of the doctrine of organic evolution, they have exerted a molding influence upon embryology to the present time. The position of von Baer in embryology is owing as much to his sagacity in speculation as to his powers as an observer. "Never again have observation and thought been so successfully combined in embryological work" (Minot).
Von Baer was born in 1792, and lived on to 1876, but his enduring fame in embryology rests on work completed more than forty years before the end of his useful life. After his removal from Königsberg to St. Petersburg, in 1834, he very largely devoted himself to anthropology in its widest sense, and thereby extended his scientific reputation into other fields.
If space permitted, it would be interesting to give the biography[6] of this extraordinary man, but here it will be necessary to content ourselves with an examination of his portraits and a brief account of his work.
Portraits.—Several portraits of von Baer showing him at different periods of his life have been published. A very attractive one, taken in his early manhood, appeared in Harper's Magazine for 1898. The expression of the face is poetical, and the picture is interesting to compare with the more matured, sage-like countenance forming the frontispiece of Stieda's Life of Von Baer (see Fig. 65). This, perhaps the best of all his portraits, shows him in the full development of his powers. An examination of it impresses one with confidence in his balanced judgment and the thoroughness and profundity of his mental operations.
