34 CHARLES F. W. McCLURE 



and the ventral surface of the vertebral column were also stained 

 a deep blue. 



Dye was stored in the stellate cells of the liver capillaries, but 

 not to the extent observed in Experiment 13 d. Dye was stored in 

 abundance, however, in the epithelium of a number of tubules in 

 the kidney and an occasional deeply stained mononuclear cell in 

 the intertubular tissue was also found. Mononuclear cells con- 

 taining dye granules were observed in the spleen. No dye was 

 stored in the oviducts or ovary but an occasional mononuclear 

 containing dye granules was found in the connective tissue of 

 the lung. 



The above experiments clearly show that solutions of colloidal 

 acid dyes pass freely through the integument of both larval and 

 adult frogs and toads, and that after reaching the general cir- 

 culation the dye is stored in part by the kidneys, and in part by 

 certain other typical tissues. 



Experiments in which the portal of entry of the dye is restricted 

 to the integument indicate that the mononuclear leucocytes are 

 among the first, if not the first of the macrophages to store the 

 dye, and that the epithelium of certain tubules in the kidneys 

 also stores the dye prior to the stellate cells of the liver capillaries. 

 The above experiments were not made with the intention of 

 determining the rapidity with which certain typical cells might 

 react toward the dye in adult frogs and toads. When compared 

 with Experiments 1, 2, 3 and 4, however, it is seen that they still 

 further bear out the view that the storage of dye granules by 

 typical cells may be accomplished in a much shorter time after, 

 than before the critical ontogenetic larval stage has been reached. 

 (Chapters 3, 5 and 7.) 



B. Feeding experiments on adult frogs and toads (table 9} 



It is difficult to state definitely the amount of dye which actu- 

 ally reached the intestinal canal at each feeding. Some indi- 

 viduals are good feeders, so to speak, and retain the dye, while 

 others often eject a good deal of it after being fed. The essential 

 feature in all of these feeding experiments is to get sufficient dye 



