X44 THE HISTORY OF BIOLOGY 



pages full of enthusiastic praise of the Creator, of effusive outpourings re- 

 garding the life of the angels and the existence of the human soul in another 

 life, in order to find amongst it all biological observations of lasting value 

 and shrewd theoretical discussions on natural-scientific problems. Bonnet 

 bases the whole of this speculation, so widely at variance with the spirit of 

 his age, on Leibniz, who, we may remember, strove to reconcile the Christian 

 beliefs with the results of natural science and philosophical thought. Haller's 

 fervently Christian conception of nature also strongly influences Bonnet, 

 who, having sprung from the high-conservative and strictly Calvinistic 

 patrician class of Geneva, was perhaps even in his youth opposed to that 

 tendency to free-thinking which prevailed in most contemporary scientific 

 circles. 



Bonnet's discovery of parthenogenesis 

 Bonnet takes his place in the history of biology primarily as the discoverer 

 of parthenogenetic reproduction. For years he studied the reproduction of 

 the aphides, and succeeded in establishing the existence of a number of sum- 

 mer hatches of females who without fertilization propagate by producing 

 live offspring; towards the autumn a new generation arises, this time con- 

 sisting of males and females, which mate, the females then laying eggs, 

 which hibernate. He also discovered and studied other peculiarities of insect 

 reproduction, as, for instance, the peculiar propagation of the pupiparous 

 flies. Further, Bonnet followed up with great care the study of the phenomena 

 of division and regeneration which Trembley had discovered; he observed 

 a large number of lower, colonizing animals, belonging to the Coelentera and 

 the Bryozoa, and experimented with them, as also with fresh-water Annel- 

 ida and common earthworms, observing not only the regeneration which 

 results in normal individuals, but also such as results in malformations — 

 in this respect a precursor in a special field of research, which has been 

 very highly developed in modern times. He studied with great exactness 

 the metamorphosis of insects, endeavouring to discover what changes the 

 parts and organs of the body undergo in the process of evolution from larva, 

 through the pupal stage, to the imago; and at least as far as the intestinal 

 canal is concerned he made, on the whole, correct observations. Again, he 

 studied the adipose tissue and the part it plays during the metamorphosis 

 period of insects as reserve nutriment for the prospective individual. Bonnet 

 also experimented with plants and was one of the first to study their tropisms 

 and growth-movements. The whole of this valuable collection of facts, 

 however, he accumulated to form the basis of his theoretical speculations 

 upon life on the earth — one might even say, in the universe — which were 

 to him the most essential function of science. 



