600 
DR. T. WILLIAMS ON THE BLOOD-PROPER AND 
are not based upon observed facts, but upon general views. He makes no allusion 
whatever to the relations which subsist between the chylaqueous system and that of 
the true blood ; he has not defined the difference in the mechanism of solid nutrition 
as it occurs respectively under the agency of these two orders of fluids. M. Quatre- 
FAGES has seized no one clue to the demonstration of the capital law of structure, viz. 
that the system of the blood-proper only first appears in the series at the Echinoder- 
mata. Unguided by this great and novel principle, he could not perceive that a 
blood-proper system could not exist, as it was not required helow the Echinodermata, 
He affords no proof of having known that the chylaqueous system of fluid is governed 
physiologically and chemically by laws distinct from, though not less definite than 
those which regulate that of the true blood. He has accumulated no individual ob- 
servations illustrative of the histological characters of the morphotic elements, either 
of the chylaqueous fluid, or the true blood. M. Quatrefages appears also to have 
been totally unacquainted with the interesting fact announced in this paper, that in 
histological structure, the corpuscles of the chylaqueous fluid are as definite and 
constant as those of the blood of the higher animals. It thus appears that, although 
the views of M. Quatrefages and those advocated in this paper proceed for a short 
distance in parallelism, they soon diverge towards two very different destinations*. 
* Having stated in the text, in general terms, the most prominent features which distinguish the admirable 
memoir of M. Quatrefages from this paper, I am here desirous that this meritorious observer should speak 
for himself, and that my observations (submitted to the Royal Society six months before the advantage 
occurred to me of perusing the original memoir of M. Quatrefages) should be fortified and justified by the 
independent researches of one so much better known to European science. I only cite so much of the memoir 
of M. Quatrefages as really bears upon the subject of this paper. I quote entire his observations on the 
microscopic examination " du liquide de la caviti gMrale ■. — “Chez les Invertebres, dont la cavity gen^rale 
communique avec le tube digestif, le liquide que renferme cette cavite est toujours compose d’eau tenant en 
suspension des particules trbs tenues provenant des aliments. Chez les Mollusques, les Insectes, les Crustac^s 
dont la cavite generale communique avec I’appareil circulatoire, le sang s’epanche librement dans cette cavity. 
Je I’ai generalement trouve compose d’un liquide incolore, charriant des granulations irregulieres, transparentes, 
sans couleur, et qui semblaient assez souvent resulter de la soudure fortuite de granulations plus petites. On 
sait, du reste, que la description que je donne ici ne s’applique pas a tous Mollusques. Depuis longtemps on a 
signale la couleur rouge violac^e du sang du Planorbe come. J’ai retrouv^ quelque chose d’analogue dans le 
Planorbe imbrique. Cette espbce est d’autant meilleure a signaler, que la transparence de sa coquille permet de 
I’observer sur le vivant. Enfin, une des exceptions les plus remarquables h citer a decouverte par M. Edwards. 
Ce naturaliste a trouve en Sicile une Ascidie dont le sang, h la vue simple, est d’un beau rouge. Au microscope, 
on reconnait que cette couleur est due a des globules framboises, tres reguliers, nageant dans un liquide incolore. 
Chez les Anneles, dont la cavite g^n^rale est close, j’ai ^galement trouve presque toujours cette cavitd remplie 
par un liquide incolore, tenant en suspension des granulations irregulieres de forme et de volume tr^s variables, 
egalement transparentes et sans couleur, mais rdfractant la lumiere avec beaucoup plus d’energie que le liquide 
ambiant ; toutefois j’ai deja fait connaitre quelques exceptions, entre autres dans le memoire sur la famille des 
Nemertiens et dans une note sur le vaisseau dorsal des Insectes. Mes observations ont porte principalement 
sur les Annelides. Dans I’immense majorite des cas, ce que j’ai vu chez elles s’accorde avec la description 
generale que je viens de donner ; pourtant j’ai encore ici des exceptions h signaler. Chez la Polyno6 lisse, le 
liquide dont nous parlons charrie des globules ovalaires, aplatis, incolores, pr^sentant I’aspect d’une substance 
homogfene refractant la lumiere h peu pres comme le liquide ambiant, et renfermant un noyau plus r^fringeut. 
