340 HEREDITY. 



pointed director of the Loan and Trust Bank of Moravia. He was 

 finally completely turned aside from his researches by the law of 

 1872 concerning religious communities, which, by this law, were 

 obliged to pay an additional tax, that amounted in the case of the 

 convent of Briinn to 5,000 florins per annum. 



Mendel, who was very headstrong, fought to the end of his life 

 against this law, which he considered unjust, and which was, in 

 fact, quietly repealed a short time after his death by another minis- 

 try. His health began to fail about 1874, perhaps under the influence 

 of a chronic nicotism. He had acquired the habit of smoking very 

 strong cigars, a practice which had been recommended to him by a 

 phj^sician, to reduce his obesity (hereditary in his family). He died 

 in 1884, at the age of 64, from Bright's disease. 



The sagacious discovery of ISIendel remained then unnoticed. 

 About 1900, more than thirty j^ears afterwards, certain biologists 

 undertook in their turn, independently^ of each other, some experi- 

 ments in heredity. De Yries (Amsterdam), Correns (Tubingen), 

 and Tschermak (Vienna), operating upon plants, rediscovered the 

 law of Mendel and brought to light his work. In the zoological 

 field. Bateson (Cambridge), experimenting with domestic fowls, and 

 myself with mice, showed that the law applied to various characters 

 of animals. Since that time numerous works have appeared, and 

 the list of characters that, in the most varied animal and vegetable 

 groups, follow the law of Mendel, has been considerably augmented. 

 It formulates a type of heredit}^, which is the most frequent of all, 

 and it may be the only one. 



It should not be supposed that it is always easj" to demonstrate the 

 law of Mendel, as has been clone in the example cited above. In 

 that only two characters were taken (G and B), and these were 

 opposed to each other. There are, however, other races that differ 

 from each other, not by one germinal character alone, but by several, 

 independent of each other, some of them being dominant, others 

 dominated as regards complementary characters of the opposite race. 

 The crossing of hybrids then gives such complicated results that 

 the application of the Mendelian laws is not readily perceived. 



For example, let us examine another diagram (fig. 3), more com- 

 plicated than the last, in which is shown the scheme of the crossing 

 of two races of mice whose germinal i^lasma presents three differen- 

 tial characters, which may be put in evidence bj^ patient analysis. 



I cross a white mouse with red eyes with another mouse also hav- 

 ing red ej^es but with yellowish brown hair; it is logical to suppose 

 that the descendants will have red eyes like the parents, and that their 

 hair will be either yellow or white; now, this is'not at all what hap- 



