TABLE OF CONTENTS. 



INTRODUCTORY. 



Pages 



A branch of Comparative Psychology little known. Defini- 

 tion of Micro-organisms. Their classification. Main 

 groups of animal Micro-organisms. Complexity of their 

 life of relation. The Micro-organism not simply an irrita- 

 table cellule... 1-4 



THE MOTORY ORGANS AND THE ORGANS OF SENSE. 

 MOTORY ORGANS. 



Motility. The pseudopod. Opinion of M. Rouget relative 

 to the formation of pseudopods. The vibrat'ile cilia. 

 Their morphological significance. Observations of Engel- 

 mann. The movements of the vibratile cilia are subject 

 to the will of the animal. Observations of M. Balbiani 

 upon the Didinium nasutum. Experiments of Rossbach. 

 The flagellum. Diversity of its movements. Observa- 

 tion of Biitschli upon the flagellum of the Glenodinium 

 fine turn. Metabolic infusoria. The granulous bands and 

 bright filaments. The contractile vesicle. The move- 

 ments of Bacteria and Gregarinae 4-20 



THE NERVOUS SYSTEM. 



Absence of a central nervous system in single-celled organ- 

 isms. Hypothesis of a diffused nervous system. Obser- 

 vation of Gruber upon the Stentor in process of division . 20-22 



THE ORGANS OF SENSE. 



Organs of touch. Organs of sight. Ocular spot in Flag- 

 ellates. Ocular spot of vegetable zoospores. Experi- 

 ments of Klebs upon the structure of these spots. The 



