378 Mr. H. J. Carter on the Nutritive and 



reflection which his observations cast on the statement that, 

 in my experiments, the carmine or " colouring-matter was 

 wholly confined to the ampullaceous sacs." But then he 

 ought to have been acquainted with that of Lieberklihn to 

 which I have alluded, and which is in the page preceding that 

 to which he has called attention (no. 20, p. 371, footnote), and 

 again in 1857, viz. " in Wasser befindliche Karminkornchen 

 sieht man hier aus dem grossen Hohlraum unmittelbar in 

 jene Wimperapparate gelangen " (no. 7, p. 385). That I 

 should have made the statement in 1857 that the carmine was 

 " wholly confined to the ampullaceous sacs " is no excuse for 

 an observer in 1879 exclusively mentioning the cells of the 

 parenchyma as engaged in this process. 



Besides, in feeding the calcareous sponges with carmine 

 and indigo respectively, the colouring-matter has always 

 appeared to me to be so confined to the sponge-cells (spongo- 

 zoa) of the ampullaceous sacs, that I have not sought for it 

 anywhere else ; while I have sometimes seen the green germ 

 of an Alga, together with the colour-particles, in the body of 

 a spongozoon. 



Nevertheless our thanks are due to Metschnikoff for having 

 especially pointed out that the mesodermal cells are capable 

 of taking in nutritive material and digesting it, because, toge- 

 ther with what had gone before, it is now shown that whether 

 ciliated and in the ampullaceous sac, or unciliated and in the 

 parenchyma, the sponge-cell generally is at least an alimen- 

 tary organ ; and thus the " conflicting statements " to which 

 I have alluded become reconcilable. 



Should the reader be inclined to recur to my paper in the 

 1 Annals ' of 1849, he will there find the following para- 

 graphs : — 



" If a seed-like body which has arrived at maturity be placed 

 in water, a white substance will, after a few days, be observed 

 to have issued from its interior, through the infundibular 

 depression on its surface, and to have glued it to the glass ; 

 and if this be examined with the microscope, its circumference 

 will be found to consist of a semitransparent substance, the 

 extreme edge of which is irregularly notched or extended 

 into digital or tentacular prolongations, precisely similar to 

 those of the protean [Amoeba], which, in progression or in 

 polymorphism, throws out parts of its cell in this way (pi. iv. 

 fig. 2, c). In the semitransparent substance may be observed 

 hyaline vesicles of different sizes, contracting and dilating 

 themselves as in the protean (fig. 2, d), and a little within it 

 the green granules so grouped together (fig. 2, e) as almost 

 to enable the practised eye to distinguish in situ the passing 



