214 BIOLOGY AND ITS MAKERS 
It has been impossible to discover a portrait of Wolff, 
although I have sought one in various ways for several years. 
The secretary of the Academy of Sciences at St. Petersburg 
writes that no portrait of Wolff exists there, and that the 
Academy will gratefully receive information from any source 
regarding the existence of a portrait of the great acade- 
mician. 
His sincere and generous spirit is shown in his correspond- 
ence with Haller, his great opponent. ‘“‘ And as to the matter 
of contention between us, I think thus: For me, no more 
than for you, glorious man, is truth of the very greatest con- 
cern. Whether it chance that organic bodies emerge from 
an invisible into a visible condition, or form themselves out 
of the air, there is no reason why 1 should wish the one were 
truer than the other, or wish the one and not the other. And 
this is your view also, glorious man. We are investigating 
for truth only; we seck that which is true. Why then should 
I contend with you?” (Quoted from Wheeler.) 
Ture PERIop oF Von BAER 
What Johannes Miiller was for physiology, von Baer 
was for embryology; all subsequent growth was influenced 
by his investigations. 
The greatest classic in embrvology is his Development of 
Animals (Entwickelungsgeschichte 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 manu- 
script. 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. 
