RECENT ADVANCES IN KNOWLEDGE OF INVERTEBRATE 

 RENAL FUNCTION* 



Arthur W. Martin 

 University of Washington 



From the position of advantage which we now occupy because of the 

 accomplishments of earlier workers, we can look back over a long accumu- 

 lation of facts about the excretory organs of invertebrate animals. Detailed 

 descriptions of the gross and microscopic anatomy are available for many 

 species. Intelligent inferences as to function are possible from a knowledge 

 of the structure, and many of these inferences have been confirmed by the 

 cytological picture following special methods of treatment of the tissues, 

 and more recently by quantitative analysis. Adequate reviews devoted pri- 

 marily to this type of work have been prepared, as for example the review 

 of the renal histology of molluscs by Turchini (1928), those of Bruntz 

 (1904) and Lison (1942) on the arthropods, and that of Willem (1910) 

 on flatworms, annelids, molluscs, and several minor phyla. 



A special case of the histological approach has been called for some time 

 the method of "physiological injection." Nonfatal doses of vital dyes were 

 injected into living animals, some time was allowed to pass, and the ani- 

 mals were then fixed and sectioned for the identification of the cells and 

 organs which responded specifically by the accumulation of the injected 

 material. Such studies appear to have identified organs which are excretory 

 by virtue of the accumulation within tliemselves of specific compounds, the 

 removal from the circulating blood being essentially complete, and these 

 structures have been called the kidneys of accumulation by some authors. 

 The distinction of these from kidneys of elimination has been broken 

 down to some extent by the realization that, at a more propitious moment 

 from the standpoint of the availability of water, the cells of accumulation 

 may lose the accumulated wastes and revert to ordinary status. For 

 examples of recent studies of this kind attention is called to a paper of Palm 

 ( 1952) on insects and one by Husson ( 1951 ) on an amphipod. 



As an appropriate immediate descendant of the morphological studies, 

 biochemical methods have been applied to the problem of excretion in in- 

 vertebrates. The very important generalizations that have been estab- 

 lished regarding the form of excretion of nitrogenous wastes may be men- 

 tioned here as a magnificent accomplishment of this method of study. 



* It is a pleasure to acknowledge the long-continued support of the Biology Branch, 

 Office of Naval Research, which has made it possible for me to conduct the investiga- 

 tions of African snail and octopus kidney function referred to in this review. 



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