CHLOROPHYLL-CORPUSCLES AND AMYLOID DEPOSITS. 253 



form, especially in the latter, is very varied. In some the 

 green colour is very partially deposited in granules and 

 superficial caps, in others it is absent altogether, and the 

 corpuscle is irregular and angular in form. 



Conclusion as to the parasitic or non-parasitic nature of the 

 chlorophyll-corpuscles of Hydra and Spongilla. — The final 

 conclusion to which we are led in relation to the chloro- 

 phyll-corpuscles of Spongilla and Hydra is that a careful 

 study of these bodies reveals in both cases their correspon- 

 dence with the known structure of the chlorophyll bodies of 

 plantSj and that those who, like Semper and Brandt, have 

 supposed these chlorophyll-corpuscles to be parasitic, have 

 been misled by, firstly, an imperfect acquaintance with the 

 characters of chlorophyll bodies in general and of these in 

 particular, and, secondly, by the plausible but delusive 

 analogy presented by the " yellow cells " of Radiolarians 

 and of Anthozoa. 



As to the nature of these latter bodies, I have no observa- 

 tions to offer. 



The chlorophyll-corpuscles of Spongilla and Hydra in 

 relation to Pringsheim's theory of chlorophyll. — Now that 

 we have established the occurrence of *' chlorophyll,'* or the 

 combined substances which together constitute that pigment, 

 in Spongilla, and with nearly equal certainty in Hydra, and 

 also have come to the conclusion that the " chlorophyll " is 

 formed in corpuscles in the cells of those animals just as it 

 is in green plants, it becomes very important to know 

 whether the chlorophyll in the animal is serving the same 

 purpose as it is in the plant; and if so, whether we may not 

 be able to get indications from the animals as to the disputed 

 function of the green pigment, such as plants are unable to 

 furnish. 



There is no doubt a field for experimental inquiry here, 

 and with the memoir of Pringsheim in his hand the zoolo- 

 gist may carry out a variety of inquiries upon " animal 

 chlorophyll," 



I would here only briefly insist on one or two remarkable 

 facts which are apparent, and which bear upon the general 

 question of the function of chlorophyll. 



In the first place, what we may call " greenless " Spongilla 

 and " greenless " Hydra flourish abundantly in the same 

 waters with green-coloured Spongillse and green-coloured 

 Hydrse. Hence, whatever value attaches to the chlorophyll — 

 it cannot be a very great one in relation to the vital pro- 

 cesses of these animals. 



In the second place, no starch can be found in immediate 



