ITS VITAL PROPERTIES, AND RELATIONS TO LIVING ORGANISM. 205 



the most characteristic elements of the Red ; and if it be admitted that they 

 are both to be looked upon as having the same origin, and as differing only in 

 their stage of development, it is manifest that no other difference can fairly be 

 expected to exist in their contents than that which is marked by the formation of 

 the coloring matter, as the final effort of their transforming power. This pro- 

 duct, as we have seen ( 142) constitutes but about one-twentieth of the whole 

 contents of the Red corpuscles. The following observation by Mr. Newport 

 seems to indicate that the corpuscles of the blood of Insects (some of them in 

 the condition of " granule-cells," others in that of " nucleated colorless cells," 

 147) have an important function to perform in the elaboration of nutrient 

 material. The " oat-shaped" corpuscles (the " granule-cells" of Mr. Wharton 

 Jones) are found, in the Larva, to be most numerous at the period immediately 

 preceding each change of skin ; at which time the blood is extremely coagulable, 

 and evidently possesses the greatest formative power. The smallest number are 

 met with soon after the change of skin; when the nutrient matter of the 

 blood has been exhausted in the production of new epidermic tissue. In the 

 Pupa state, the greatest number are found at about the third or fourth day sub- 

 sequent to the change ; when preparations appear to be most actively going on 

 for the development of the new parts that are to appear in the perfect Insect. 

 After this, there is a gradual diminution ; the plastic element being progress- 

 ively withdrawn by the formative processes ; until, in the perfect insect, very 

 few remain. When the wings are being expanded, however, and are still soft, 

 a few oat-shaped corpuscles circulate through their vessels ; but, as the wings 

 become consolidated, these corpuscles appear to be arrested and to break down 

 in the circulating passages ; supplying, as Mr. N. thinks, the nutrient material 

 for the completion of these structures, which subsequently undergo no change. 1 

 The blood also contains nucleated cells, the proportion of which seems to in- 

 crease in the Imago state, whilst that of the " granule-cells" diminishes. 



196. That condition of the corpuscular element of the blood which is normal 

 in the Insect must be considered as decidedly abnormal in the Vertebrated 

 animal, in which the circulating fluid goes on to a higher phase of development; 

 and the excess of Colorless corpuscles in the latter seems always to be associated 

 (save in the early part of life) with an imperfect performance of their nutritive 

 operations. Thus, according to the observations of Mr. Paget, they are espe- 

 cially abundant in the blood of frogs that are young, sickly, or ill-fed ; and 

 whilst in the first of these cases, their large number seems to depend upon rapid 

 increase, so that new red corpuscles may be generated in adaptation to quick growth, 

 in the two latter their accumulation seems rather to be attributable to a retarda- 

 tion of development through disease or defective nutriment, so that, although 

 their production is not hindered, their normal metamorphosis does not take 

 place. So, as regards the human subject, Mr. Paget confirms the statement of 

 Mr. Wharton Jones and Prof. J. H. Bennett, that the increased proportion of 

 Colorless corpuscles which has been regarded by some observers (especially by 

 Mr. Addison and Dr. C. J. B. Williams) as characteristic of inflammatory 

 blood, and particularly of that which is drawn from an inflamed part, is far 

 from being a constant phenomenon ; being most frequent when the subjects of 

 the disease are persons in weak health, or of the tuberculous diathesis, as has 

 been remarked also by Nasse and Popp. 3 And Mr. Paget has furnished a re- 

 markable confirmation of this view, in the observation, that the inflammatory 

 exudations produced in different individuals, by the application of the same 

 stimulus on the same tissue (e. g. by the action of a blister on the skin) are 

 found to present a predominance of the fibrinous or of the corpuscular element, 



1 "Philosophical Magazine," May, 1845. 



2 "Lectures on Inflammation," in "Medical Gazette," 1850, vol. xlv. pp. 972, 973. 



