SYMBIOLOGY — THE BIOLOGICAL RELATIONSHIPS OF ORGANISMS 143 



wasps lay their eggs directly into the tissues of the caterpillar. The 

 egg develops and the young larva feeds upon the less vital tissues of the 

 host so as to prolong Hfe as much' as possible. Finally only the outer 

 tegument of the host remains which is utilized as a protective covering 

 during the resting stage. 



We must also mention the phenomena of grafting (plant), tissue trans- 

 plantation, tumor transplantation, gland transplantation, organ transplan- 

 tation, etc. "These are usually not designated as symbioses. In successful 

 tree grafting, for example, there is estabUshed an apparently perfect sym- 

 biosis of a mutualistic character. In successful cancer transplantation 

 there is established a form of symbiosis which is truly parasitic. Skin 

 grafting, as practised in cases of severe burns constitutes a symbioid cell 

 association of the mutuaUstic t3^e. 



Phenomena of True Symbiosis. — The phenomena of symbiosis here 

 defined have been more or less discussed by scientists and have received 

 recognition. Authors are, however, at variance as to their exact limita- 

 tions which makes the definitions subjectively variable. The phenomena 

 of symbiosis may be classified as follows : 



I. Incipient Symbiosis (Indifferent Symbiosis). 



1. Accidental Symbiosis. 



2. Contingent Symbiosis (Raumparasitismus) . 



II. Antagonistic Symbiosis. 



1. Mutual Antagonistic Symbiosis (Mutual Parasitism). 



2. Antagonistic Symbiosis (Parasitism). 



* a. Obligative Antagonistic Symbiosis, 

 b. Facultative Antagonistic Symbiosis. 



3. Saprophytism. 



a. Facultative Saprophytism. 



b. Obligative Saprophytism. 



III. Mutualistic Symbiosis. 



1. Nutricism (Semi-mutualistic Symbiosis). 



2. Mutualism. 



3. IndividuaUsm. 



a. Semi-individualism. 



b. Complete Individualism. 



IV. Compound Symbiosis. 



V. Cytosis. 



1. Autocytosis. 



a. Patrocytosis — Phagocytosis, tissue regeneration, etc. 



b. Paracytosis — Epithelioma, cysts, etc. 



2. Heterocytosis. Consortism. Commensalism. 



