REFERENCES AND QUOTATIONS. 323 



selves into buds and the sexual elements ; their development de- 

 pends on their union with other nascent cells, or units, and they 

 are capable of transmission in a dormant state to successive gen- 

 erations. 



"In a highly organised and complex animal, the gemmules 

 thrown off from each different cell, or unit, throughout the body 

 must be inconceivably numerous and minute. Each unit of each 

 part, as it changes during development — and we know that 

 some insects undergo, at least, twenty metamorphoses — must 

 throw off its gemmules. All organic beings, moreover, include 

 many dormant gemmules derived from their grand-parents and 

 more remote progenitors. These almost infinitely numerous and 

 minute gemmules must be included in each bud, ovule, spermao- 

 zoon, and pollen grain. Such an admission will be declared im- 

 possible, but, as previously remarked, number and size are only 

 relative difficulties, and the eggs or seeds produced by certain 

 animals or plants are so numerous that they cannot be grasped 

 by the intellect." Darwin, Variations of Animals and Plants, 

 II. 526. 



" A. Rollet, Ueber die Erscheinungsformen des Lebens und den 

 beharrlichen Zeugen ihres Zusammenhanges. Almanach der kais. 

 Akademie der Wissenschaften (Wien, 1872). 



" Darwin, Variations of Animals and Plants, I. 200. 



"V. Graber, Ueber den Tonapparat der Locustiden, ein Beitrag 

 zum Darwinismus. Zeitschrift fiir wissenschaftliche Zoologie. 

 Vol. 22. 



'° Hermann v. Nathusius, Vorstudien fiir Geschichte und Zucht 

 der Hausthiere zunachst am Schweineschadel, 1864. 



" lb., p. 108. 



" Descent of Man, I. 412. 



" Origin of Species. 13th ed., p. 171. 



" Lamarck also constructed a pedigree at the end of his " Philo- 

 sophic Zoologique," in which he disposes of the greater number 

 of classes, while he attributes to the remainder another point of 

 derivation. He thus assumes in the animal kingdom two primordial 

 forms derived from primordial generation. His scheme is as 

 follows : — 



