1872.] Dr. H. V. Carter on the Composition of Urinary Calculi. 81 



The occurrence of colourless corpuscles in LejptocepTialus identical in 

 form and character with the Hemoglobin-bearing corpuscles of the blood 

 of other fish, and the apparently capricious distribution of Haemoglobin 

 among Invertebrata, together with the existence of the green oxygen- 

 carrier Chlorocruorin and the pink colouring-matter of the corpuscles of 

 Sipuncidus nudus, suggest the hypothesis of the existence of various bodies 

 not necessarily red, possibly colourless, which act the same physiological 

 part in relation to oxygen as does Haemoglobin. 



DESCEIPTION OF PLATE I. 



Fig. 1. Glycera. Red corpuscles acted on by acetic acid. 

 Fig. 2. Glycera. Red corpuscles acted on by magenta. 



Fig. 3. Glycera. a to /, normal red corpuscles ; g, seen laterally ; h, i, testicular cell- 

 masses ; Jc, leucocyte ; J, I, ova. 



Fig. 4. Solen legumen. a, b, c, normal red corpuscles ; d, e, leucocytes of Solen ensis 

 identical with leucocytes of 8. legumen, with nucleus stained by magenta. 



Fig. 5. Solen legumen. a, b, c, red corpuscles acted on by dilute acetic acid ; d, e, f, g 

 ditto acted on by magenta. 



Fig. 6. Pkoronis hippocrepia. Red corpuscles acted on by dilute acetic acid. 



Fig. 7. Sipunculus nudus. a to g, normal pink-coloured corpuscles of the perivisceral 

 fluid ; b contains a crystal ; h, leucocyte from the same fluid ; i, j, pink cor- 

 puscles (pneumocytes) acted on by dilute acetic acid. 



II. " On the Structural Composition of Urinary Calculi." By 

 H. Vandyke Carter, M.D. Lond. Communicated by L. S. 

 Beale, M.D., F.E.S. Received October 11, 1872. 



(Abstract.) 



Having occasion during his late residence in "Western India to remove 

 numerous urinary calculi from persons belonging to the indigenous popu- 

 lation, the author was enabled to pursue an inquiry into the character of 

 these concretions which he had begun in the year 1859 by the chemical 

 analysis of a large number of such calculi ; it remained then to make use 

 of the microscope as a means of investigation; and since no record of a 

 similar systematic inquiry to that now undertaken has been published, so 

 far as known to the author, it was thought desirable that this hiatus in 

 medical literature should, however imperfectly, be forthwith filled up. 



The plan adopted was to submit minute fragments taken from the real 

 or apparent nuclei, and from succeeding layers and crust, of the calculi 

 examined to the scrutiny of average optical powers, the highest available 

 magnifying about 300 diameters. Distilled water was the ordinary 

 medium employed ; and in all cases chemical tests were conjointly used 

 for the purposes of detection or confirmation. After sufficient practice, 

 it became apparent that the microscopic analysis of calculi, thus carried 



g2 



