94 
On the Blood of 
Art. II. Observations on the Blood of the Ornithorhyn- 
chus paradoxus. By Edmund C. Hobson, M.D. 
Before I enter upon a description of the blood of this 
animal, I shall notice the composition, colour, and 
shape of the blood globules in the grand divisions of 
the animal kingdom, and the analogy of the nutritious 
fluid of animals with that of vegetables. 
The existence of a nutritive fluid manifests itself in 
both the animal and vegetable kingdom. In the vege¬ 
table world it is called sap : in the lower conditions of 
the animal kingdom, nutritive fluid ; and in the higher 
grades of animal being this vital nutritious fluid is 
termed blood, and is enclosed in special vessels, which 
do not communicate by open mouths with the digestive 
canal. 
In all the vertebrate animals, the separation of the 
various humours is complete ; the nutritious juice formed 
in the digestive canal is received by endosmose into a 
particular set of vessels called lacteals, which convey it 
into the blood. 
Among the Mollusca , Crustacea , Arachnida insects, 
Annelidas , and Echinodermata , the distinction betwixt 
the nutritious fluid and the blood is effaced : the lym¬ 
phatics are absent, and the chyle or nutritious juice 
passes immediately from the digestive canal into the 
mesenteric veins. 
In those animals which are deprived of blood, there is 
no vascular system distinct from the digestive organs ; 
consequently, no difference betwixt the nourishing juice 
and vital fluid. 
In the greater number of the Acalepha , the matter 
which holds an intermediate condition between the nu¬ 
tritious juice and vital fluid is the immediate product of 
digestion ; and the prolongations of the alimentary canal 
