282 The Structure of Colored Blood- Corpuscles. 



further, " I cautiously avoided recording those which mani- 

 fested even Blight departures toward an oval form ;" but, on 

 the other hand, "to secure the most infallible accuracy for my 

 deductions, as the preparation was moved along, I measured 

 every isolated circular red disk which came into the field of the 

 microscope." 



In the year 1761, Padre Jo. Maria de Turre, of Naples, 

 made a present to the Royal Society of London of four spher- 

 ical glasses for the microscope, made by himself, of which the 

 diameters and magnifying powers were said to be as follows : 



Diameter. Magnifying Power. 



1. Near 2 Paris points. 640 times, and upward, in diameter. 



2. 1 Paris point. 1.2S0 " 



3. 1 " 1,280 " " 



4. Half a Paris point, 2,560 " " 



(1-144 of an inch.) 



Sir Francis Haskins Eyles Stiles, at the time in Naples, 

 through whom the presentation was made, wrote several let- 

 ters, in wliich he communicated Father de Turre's directions 

 for the use of the glasses, as well as an account of some obser- 

 vations on the human blood, made by him, together with 

 Turre, during July and August, 1761, and read before the So- 

 ciety during November, 1765. They saw in the blood globules 

 the central depression, which had not theretofore been ob- 

 served, and which carried with it so strongly the appearance 

 of a perforation that they concluded the corpuscles to be 

 rings. They also thought the rings to be articulated (" the 

 transverse lines at the joints being very distinguishable"). 1 

 As to their shape, " the figure of the rings, where they were 

 free, and in their natural state, was circular; but where they 

 were so crowded together as to compress one another in their 

 passage, they assumed a variety of different figures, although 

 they generally restored themselves to a circular figure again,' 



1) "Au Account of some Microscopic Observations on the Human Blood." Philosopnica 

 Transactions, vol, lv. 1765). p. 264. 



