Gray.] 118 [October 7, 



exact outlines of the cells, with all their irregularities and 

 imperfections. But I cannot refrain from citing a portion of 

 his remarks at the close : — 



" Here, as is so often the case elsewhere in nature, the type- 

 form is an ideal one ; and with this real forms seldom or 



never coincide An assertion, like that of Lord 



Brougham, that there is in the cell of the bee ' perfect agree- 

 ment ' between theory and observation, in view of the anal- 

 ogies of nature is more likely to be wrong than right; and 

 his assertion in the case before us is certainly wrong. Much 

 error would have been avoided if those who have discussed 

 the structure of the bee's cell had adopted the plan followed 

 by Mr. Darwin, and studied the habits of the cell-making 

 insects comparatively, beginning with the cells of the humble- 

 bee, following with those of wasps and hornets, then with 

 those of the Mexican bees (Melipona), and finally with those 

 of the common hive-bee. In this way, while they would 

 have found that there is a constant approach to the perfect 

 form, they would at the same time have been prepared for 

 the fact, that even in the cell of the hive-bee perfection is 

 not reached. The isolated study of anything in natural his- 

 tory is a fruitful source of error." 



Let me add to this important aphorism its fellow, which I 

 have from him, but know not if he ever printed it. "iVb* 

 single experiment in physiology is worth anything? 



The spirit of these aphorisms directed all his work. It is 

 well exemplified in his experimental researches — the last 

 which I can here refer to, upon — " The formation of Infusoria 

 in boiled solutions of organic matter, enclosed in hermetic- 

 ally sealed vessels and supplied with pure air," and its sup- 

 plement, "Observations and Experiments on living organisms 



