602 
DR. T. WILLIAMS ON THE BLOOD-PROPER AND 
elements of the surrounding water, is contained in part in the interior of, and in part 
between, the cells of the gelatinous cortex*. I have proved that this fluid, which is 
the true blood of the sponge, is composed of a mixture of salt water and albumen. 
The most organized is that contained m the cells of the gelatinous cortex, the least is 
that between the cells. These cells actually vitalize and organize the elements of 
the aerated water. The sponge presents the Jirst and simplest problem in zoo- 
chemistry -f-. 
Polypifera . — In all Polypes the space between the stomach and integuments is 
filled with a corpusculated, organic fluid, varying in different species, moving to 
and fro under muscular or ciliary agency. It is principally composed of sea-water, 
which, in passing through the stomach, blends with the secretions of this organ, and 
then enters the visceral cavity, where it acquires those vital and chemical properties 
which fit it to nourish the solids of the body. In the hydraform and actiniform 
groups it has not yet been proved that the stomach opens directly into the visceral 
cavity. The tentacles in some species are undoubtedly perforated at their distal ends, 
in order to admit the surrounding water immediately into this cavity, where it ad- 
mingles with the product of digestion, and undergoes, thus directly, the process of 
organic assimilation. In several small and transparent species of Actiniae, I have 
lately seen, with perfect distinctness, the motion of the perigastric fluid by its cor- 
puscles, and proved that the tentacles are imperforate at their distal extremities. In 
the composite forms of Polypes the bottom of the stomach communicates freely with 
the interior of the polypidom, as in Campanularia and Alcyonidium. This fluid in 
all zoophytes penetrates into all the appendages and recesses of the body. It is, in 
in the Actinia and by Will va. Alcyon Palm4, remarking, however, “ peut-etre de nouvelles recherches sont-elles 
necessaires pour s’assurer que ces observateurs n’ont pas regarde comme un appareil sanguin le systeme decrit 
par M. Edwards, et qui est en communication avec la cavitd generate des Polypes.” It appears to me to he only 
a just construction of the meaning of M. Quatrefages, as expressed by himself in the preceding passages, to 
state that he nowhere gives any clear proofs of having recognised in the fluid of “ la cavite generate du corps” 
a system of circulation, definite and distinct in its laws, which, in the lower Invertebrata, replaces and represents 
that of the blood-proper as it exists in the vertebrated animal. The justice of this criticism is rendered unde- 
niable by the tenour of the following observations : — “ Chez les Invertebres dont la cavite generale communique 
avec I’interieur, la maniere dont Pair est mis en rapport avec les principes qu’il doit modifier est evidente, et resulte 
du fait meme de I’introduction d’une eau aeree La respiration du liquide de la cavite generale est plus 
difficile a reconnaitre chez les Invertdbres dont la cavite generale est entierement close.” In the first remark he 
supposes that the fluid of the visceral cavity is the aerating medium, not itself the subject of the respiratory change. 
By the second observation he admits that the part performed by the chylaqueous system of fluid, in the Echi- 
noderms and Annelids, in the mechanism of respiration, is difficult to understand. In this critical analysis of the 
valuable memoir of M. Quatrefages ‘ On the General Cavity of the Body in the Invertebrata,’ I have, I think, 
clearly shown that there is scarcely anything in common either between the facts or arguments therein given, 
and the carefully recorded dissections and observations upon which I have sought in this communication to 
rest the superstructure of an important physiological law. 
* Annals and Magazine of Natural History, by Mr. Carter, August 1849, 
t See Observations on the Cilia of Sponges in Goodsie’s Annals of Anatomy and Physiology, May 1852. 
