584 THE HISTORY OF BIOLOGY 



Just as the right of a child to take over his parents' property is called in- 

 heritance, so the word is used to denote the fact, which has been known of 

 old, that children resemble their parents in body and soul; facial features 

 and figure are said to "be hereditary ' ' from father and mother to son and 

 daughter. It can be no matter for surprise that from the beginning the mean- 

 ing of heredity in the biological sense has been considered to be this: the 

 direct transmission of qualities from parents to children — that, in fact, 

 has been the idea up to recent times and it has not been until the details 

 of this transmission came to be studied that a deeper insight has been gained 

 into the true facts, and an entirely new conception has taken the place of 

 the old theory of transmission. It is through this research work that the 

 problems of evolution have for the first time been dealt with on an entirely 

 exact basis; the same mathematical exactness that formerly only experi- 

 mental physiology was capable of achieving now characterizes the methods 

 and results of heredity research. 



Exact heredity-research has received contributions from various quar- 

 ters. Investigators with a Darwinistic training have made weighty contri- 

 butions to it, but besides these, others — and, in fact, the most valuable 

 of all — have come from circles that have had nothing whatever to do 

 with Darwinism. In a previous section have been mentioned the investiga- 

 tions into the hybridization of plants that were carried out in the eighteenth 

 century by Koelreuter. His experiments were taken up by many other stu- 

 dents, among the most highly reputed of whom may be named Karl Fried- 

 rich Gartner (1772.-1850), a medical practitioner by profession, whose 

 elaborate experiments with plant hybrids brought him a great reputation 

 and were especially taken advantage of by Darwin. The experiments carried 

 out by the Frenchman Louis Leveque de Vilmorin (18x6-60) were of a 

 different type. De Vilmorin belonged to a family that for generations had 

 carried on trade in grain and seed-cultivation; he himself was particularly 

 interested in sugar-beet, which he cultivated with a view to increasing its 

 percentage of sugar. In this he started from the principle that the offspring 

 of each individual should always be kept separate; he collected the seeds 

 of beets with a high sugar-content and sowed them separately, with the 

 result that he obtained cultures of a very valuable quality; in doing so he 

 discovered that individuals that look alike might have entirely different 

 characters, and he thus came to hold the view that the power of inheriting 

 characters might in itself vary and give rise to heterogeneous offspring. 

 Through these results de Vilmorin became a pioneer of modern heredity- 

 research, and his theses, based, as they are, upon exact observations, possess 

 quite a different value from his contemporaries' "philosophical" specula- 

 tions on heredity, numerous traces of which are to be found, inter alia, in 

 belles-lettres of a naturalistic type. 



