166 The Microscope. 



The subject is full of stirring interest for the microscopist as 

 well as for the spectroscopist. One of the most interesting facts 

 well ascertained is, that in fish blood we often find blood corpuscles 

 with a crystal " intra-globular," and which, on addition of water, 

 resumes its normal form and condition again. This extraordinary 

 phenomenon became a subject of widespread controversy. But the 

 same " intra-globular " appearances were demonstrated in 1857 by 

 Bissegger and Bruch at the meeting of the Physical Society, assem- 

 bled at Basil, Switzerland. 



Whilst haemoglobin, or hsemato-crystalline (and we shall, in 

 future, use the first term on account of its brevity), is the normal 

 crystallizable material of blood, there are other blood crystals 

 directly derivable from blood that has been acted upon by chemical 

 agencies, and are mostly products of decomposition or chymolisis. 

 Such are, firstly, the "hsemin," and Lehman's hsematin, that 

 seems to be identical with hsemin ; also haematoidin, which appears 

 in beautiful oblique rhombic forms, and is one of the most frequent 

 of metamorphic products spontaneously formed in the body out of 

 hsematin (perhaps more properly out of haemoglobin), and is found 

 often in such large quantities that it may be perceived by the 

 naked eye. The crystals appear in a brilliant yellowish-red color. 

 When present in larger masses they present a deep ruby-red color, 

 and form, according to Virchow, the most beautiful crystals with 

 which we are acquainted. Prof. Virchow says ("Cellular Pathol- 

 ology") a man must be a keen observer, or else he will fail to 

 discover in the spots where the haematoidin is lying, any more 

 than an apparently shapeless mass. 



This substance is probably changed haemoglobin, not altered 

 haematin, as Virchow has it. 



An apoplectic effusion in the brain cannot be repaired by any 

 other process than by blood undergoing this transformation into 

 haematoidin. Virchow also believes that when a young woman 

 menstruates and the cavity of the grafian vesicle becomes filled 

 with coagulated blood the (haematin?) haemoglobin is gradually 

 converted into haematoidin, and we afterwards find, at the spot 

 where the ovum has lain, the beautiful, deep-red, oblique rhombic 

 crystals as the last memorials of menstrual episodes. In this 

 manner we can demonstrate apoplectic attacks in the brain, and 

 calculate how often the menstrual process has taken place. Often 

 this is of great importance in forensic cases. 



These crystalline deposits of haematoidin possess the 



