THE-ORGH ID REVIEW: 
Vot. XIV.] APRIL, 1906. {No. 160. 
THE MENDELIAN “LAWS” OF INHERITANCE. 
THE meeting of the Scientific Committee on March 2oth was devoted to 
an exposition of the Mendelian Theory of Inheritance, by Mr. C. C. Hurst, 
F. L. S., and was held in the Council Room, numerous Fellows interested 
in the subject being also present. 
Mr. Hurst alluded to the experiments of Mendel in hybridising peas, 
when it was observed that of two given characters in the parent one was 
dominant over the other in the hybrid. Thus he crossed peas having 
round and wrinkled seeds, yellow and green cotyledons, purple and white 
flowers, tall and dwarf stems, inflated and constricted pods, green and 
yellow pods, axial and terminal flowers, and found the first-named character 
dominant over the other, which latter he called recessive. This was 
termed the “ Law af Dominance,’ and Mr. Hurst remarked that in 
numerous characters in plants and animals he had found it to hold 
good ; in Orchids, amongst others, sap-coloured being dominant over white 
flowers, and spotted over striped. 
When the hybrids were self-fertilised Mendel found that segregation 
or splitting of the characters took place, in the ratio of three dominants to 
one recessive, thus the hybrids between yellow and green peas when self- 
fertilised gave on the average 75 per cent. yellow and 25 per cent. green, 
both types often appearing in the same pod. This was termed the “* Law 
of Segregation,” and Mr. Hurst had also confirmed this in his experiments 
with plants and animals, the recessive character after “‘ skipping a genera- 
tion” reappearing apparently unchanged. 
In the third generation Mendel found that the extracted recessives bred 
true, without reversion to their dominant ancestors, e.g., the green peas 
extracted from the yellow-green hybrids bred true greens, with no trace 
of yellow. The yellow dominants were tested in the same way, and in the 
second generation two types of yellow were found, one that bred true, and 
one that retained the hybrid characters, and these were in the ratio of one 
to two. These were termed respectively pure dominants and hybrid 
a 
The were continued to the seventh generation, 
P 
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