PREFACE. v 



an organism grows more perfect and complex. Nothing could be 

 more inconsistent with the teachings of general physiology, which 

 shows us that all vital phenomena are previously present in non- 

 differentiated cells. 



Furthermore, it is interesting to note to what conclusion the 

 admission would lead as Romanes apparently does admit that 

 psychological properties are wanting in lower-class beings and that 

 they enter at different stages of zoological development. Romanes 

 has minutely particularized on a large chart the development of the 

 intellectual powers, in quite an arbitrary manner. According to 

 his scheme, only protoplasmic movements, and the property of 

 excitability are present in lower-class organisms. Memory begins 

 first with the echinoderms; the primary instincts with the larvae of 

 insects and the Annelids; the secondary instincts, with insects and 

 spiders; reason, finally, commences with the higher Crustaceans. 



I do not hesitate to say that all this laborious classification is 

 artificial in the extreme, and perfectly anomalous. 



All writers that have devoted themselves, with any pretension 

 to special investigation, to the study of unicellular organisms, have 

 attributed to these beings most of the psychological properties 

 which M. Romanes reserves for this or that higher-class animal. 

 This is the opinion of Gruber, of Verworn, of Moebius, of Balbiani, 

 and of many other naturalists. Moebius recognizes that psycho- 

 logical life begins with living protoplasm, and he considers it to be 

 the highest aim of zoology to demonstrate the psychical unity of all 

 animals. 



We could, if it were necessary, take every single one of the 

 psychical faculties which M. Romanes reserves for animals more 

 or less advanced on the zoological scale, and show that the greater 

 part of these faculties belonged equally to Micro-organisms. But 

 we must not unnecessarily extend the discussions of this introduc- 

 tion. We shall accordingly limit ourselves to few illustrations. 



M. Romanes, in his zoological scale, assigns the first manifes- 

 tations of surprise and fear to the Iarva5 of insects and to the An- 



