346 Dr. T. Williams on the Mechanism of Aquatic 



poses that the intervention of cells in the nutritive fluids is 

 neither indispensable to the process of solid nutrition nor to that 

 of respiration. 



It is a fact of surpassing physiological interest that the chyl- 

 aqueous fluid in the Sirongylus of the sheep, which can be col- 

 lected by spoonfuls, is nothing hut a thick solution of albumen. 

 After even prolonged standing, it does not throw down the 

 slightest vestige of fibrine-clot. If " the blood " of the infested 

 animal permeated through the integuments of the parasite, 

 and thus reached the visceral chamber of the latter, it appears 

 probable that both the fibrine and the red corpuscles of the 

 former would be capable of detection in the chylaqueous fluid of 

 the latter. This, however, is not the case. The cyst in which 

 Trichina spiralis is lodged in the substance of the muscle is 

 filled with a fluid in which both the fibrine and the red cor- 

 puscles of the infested animal can be readily shown to exist. The 

 inference is obvious. The chylaqueous fluid of the worm is not 

 derived directly from without by filtration through the partition 

 of the cutaneous structures. 



In the order of Nematoid worms, typified by the Strongylus 

 of the sheep, the integuments are very thin ; the spaces be- 

 tween the circular muscular fasciculi being covered by little 

 more than the epidermis — conditions well-fitted to favour the 

 interchange of gases between the chylaqueous fluid within and 

 the aerating medium without. No indications of vibratile epi- 

 thelium in any structure in any species of Nematoid worms can 

 be discovered on the general cutaneous surface, dedicated though 

 it be unquestionably to the office of respiration : they exist in no 

 instance. Why do they not exist ? The organic law presiding 

 over the development of these motive organules is still beyond the 

 ken of science. 



Henceforth it will not satisfy the physiologist to affirm, in the 

 vagueness of a general phrase, that " the respiration is cuta- 

 neous." He must know, with exact definition, by which order 

 of fluids that function is enacted, and whether the living fluid, 

 immediately influenced by the external element, be charged or 

 not with morphous particles. Superstition for ages has wrapped 

 these uninviting beings in unresolvable mist. The assertion has 

 now been abundantly supported, that the process of respiration 

 in all Entozoa is conducted on the aquatic model — that the 

 chylaqueous fluid, though non-corpusculated, is by far the most 

 voluminous and important fluid element in the organism, and 

 that which directly performs the function of breathing. The 

 true blood when it exists is only secondarily aerated. The ' value ' 

 of the respiratory function is directly proportional to the organic 



