THE BLOOD AND THE LYMPH. 337 



in the heart. 5. cells resembling pus- corpuscles, in tumours of 

 the spleen and leukaemia (Virchow) ; these bodies are found 

 in vast quantities, but, in their form, cannot in any way be dis- 

 tinguished from the colourless blood-corpuscles. 6. caudate, 

 pale or pigmented cells (Virchow, 'Arch./ II). Besides these, 

 should be noticed, the morphological elements which are formed 

 in the blood without the body or in cases where the circulation 

 has been obstructed — the fibrinous coagula and crystals. The 

 former are seen in coagulated blood, usually in the form of fine, 

 extremely closely interwoven fibrils, disposed irregularly ; oc- 

 casionally as stronger, straiter fibres, having a uniform width of 

 0*001 — G'03"'; not unfrequently also in the shape of plates 

 resembling epidermis- scales (fibrinous flakes, Nasse). I noticed 

 c?*ystals of a red colour in normal blood in the year 1849 

 ('Zeitsch. fur wissen. Zool./ I, p. 266, Todd's 'Cyclop, of Anat.' 

 Art. ' Spleen/ p. 792, and Mikros. Anat., II, p. 280), in the 

 blood of the Dog, of Fishes, and of a Python; sometimes 

 within the blood -globules, sometimes free in the blood, par- 

 ticularly of the liver and spleen. Their occurrence in the 

 former situation especially, appeared to me to prove that they 

 exist in the blood during life, and consist of a substance allied 

 to hematin and hematoidin (Virchow) ; but I also showed that 

 they were soluble in acetic and nitric acids, and in caustic 

 alkalies, and consequently that they are not identical with 

 hematoidin. Quite recently, Funke, without being acquainted 

 with my observations, has independently noticed these crystals 

 in the blood of the Horse, Dog, Man, and Fishes, and instituted 

 very careful researches with respect to them (' De sanguine venae 

 lienalis/ Lips., 1851 j also in Henle's 'Zeitsch. N. Folge/ Bd. I, 

 p. 172, and 'Neue Beob. iib. d. Krystalle d. Milzvenen- u. 

 Fischblutes/ ibid., II, p. 199), by which it is rendered certain 

 that these crystals arise out of the body. For more particulars 

 concerning them reference may be made to the works cited, 

 and I will here only further notice that the crystals are most 

 readily formed, if a drop of blood covered with a piece of glass 

 be allowed nearly to dry, and a small quantity of water be 

 added; moreover, that the crystals are formed not only in the 

 blood of the splenic vein, as it at first seemed, but in other kinds 

 of blood also, in Man (I can obtain crystals in my own venous 

 blood) and other animals. They assume the form of red or 

 ii. 22 



