CHAPTER IX 



31. Miscellaneous Investigations on the Histological Structure of 



Hybrids 



THE contributions here under consideration, of Macfar- 

 lane, Henslow, Wilson, and Darbishire, are devoted largely 

 to the study of the details of the histological characters 

 of a considerable number of plants and of their hybrids in the 

 first generation. Although the work of the last-named investigator 

 came after the rediscovery of Mendel, the work of Darbishire on 

 peas is included because of the interest attaching to work with this 

 plant, and its relation to the general subject of Mendelism. 



a. Henslow. 



The paper of J. S. Henslow (5), "On the Examination of a 

 hybrid Digitalis," read November 14, 1831, and published in the 

 Transactions of the Cambridge Philosophical Society, 4:257-78 

 (1833), while minor in extent, was perhaps the first paper on 

 hybrids, since the publications of Sageret, which attempted to deal 

 with characters of the hybrid and of its parents from the com- 

 parative standpoint, and, to some extent, in terms of measure- 

 ment. It is certainly the first paper of the sort to appear in 

 English. 



Henslow, while Professor of Botany at Cambridge University, 

 states that : 



"chance having favored me with a hybrid Digitalis during the past 

 summer [1831], in my own garden, I employed myself, whilst it con- 

 tinued to flower, which was from June 19 to July 22, in daily examining 

 its character, and anatomizing its parts of fructification. I was careful to 

 compare my observations, with as much patience and accuracy as I can 

 command, with the structure of its two parents. It seemed to me not 

 unlikely that something interesting might result from a rigorous exami- 

 nation of this kind, or at least that its recorded details might serve as a 

 point of departure for future observations." (p. 257.) 



The plant, according to Henslow (^), was a natural garden 



cross between Digitalis lutea and D. purpurea. The seeds of each 



