TABOO AND GENETICS 5 



There are a number of other forms of asexual 

 reproduction, or the " vegetative type " (Ab- 

 bott's term, which includes fission, budding, 

 polysporogonia and simple spore formation). 

 Budding (as in yeast) and spore formation are 

 familiar to us in plants. Such forms are too 

 distant from man, in structure and function, for 

 profitable direct comparison. Especially is this 

 true with respect to sex, which they do not 

 possess. 



Parthenogenesis includes very diverse and 

 anomalous cases. The term signifies the abiUty 

 of females to reproduce in such species for one 

 or a number of generations without males. 

 Many forms of this class (or more strictly, these 

 classes) have apparently become speciahzed or 

 degenerated, having once been more truly 

 sexual. Parthenogenesis (division and develop- 

 ment of an egg without the agency of male 

 sperm) has been brought about artificially by 

 Jacques Loeb in species as complicated as frogs. 

 (i, 2.) All the frogs produced were males, so 

 that the race (of frogs) could not even be 

 theoretically carried on by that method. 



The origin of sexual reproduction in animals 

 must have been something as follows : The first 

 method of reproduction was by a simple division 

 of the unicellular organism to form two new 

 individuals. At times, a fusion of two in- 

 dependent individuals occurred. This was 



