ADDITIONS AND NOTES TO VOL. I. 485 



and Moleschott* in that of the connective tissue, and of the liga- 

 mentum nuchac ; and I have found the same substance in all con- 

 tractile tissues, which contain contractile fibre-cells (smooth mus- 

 cular fibres). 



Stasf found a similar substance in the fluid of the allantois. 



(44) Addition to p. 38fi, line 15. 



THE CRYSTALLINE SUBSTANCE OF THE BLOOD. 



Properties. This substance is distinguished from all other 

 protein-bodies by the readiness with which it crystallises ; but this 

 very property merely indicates that we have not here to deal with 

 a matter which is perfectly identical for all classes of animals, how- 

 ever extraordinary may be the resemblance existing between its 

 different modifications ; the crystals of the blood occur principally 

 in three forms, namely, in prisms, tetrahedra, and hexagonal tablets. 

 The prismatic forms, whose true system of crystallisation has not 

 been firmly established notwithstanding the attention which has 

 been devoted to the subject, are peculiar to human blood and to the 

 blood of most mammals and fishes ; the tetrahedra are met within 

 some of the rodents, as for instance, in guinea-pigs, rats, and mice, 

 while the hexagonal tablets have hitherto been found only in 

 squirrels. These crystals contain water of crystallisation, but lose 

 it with tolerable rapidity when exposed to the air ; they do not, how- 

 ever, at once fall to powder, but only partially contract and become 

 irregular, still retaining a tolerable amount of water, as they are 

 extremely hygroscopic. They are devoid of smell and taste ; they 

 are always red in colour, appearing of a peach-blossom or purplish 

 red tinge when seen under the microscope ; they are of a light 

 cinnabar red when in masses, and of a yellowish brown colour 

 when dried and pulverised. The solubility in water of the different 

 forms of crystals is very different: thus 1 part of the tetrahedric 

 crystals dissolves in 600 parts of water, while 1 part of the pris- 

 matic crystals from the dog requires no more than 90 parts of water ; 

 the solubility of the hexagonal crystals is nearly equally removed 

 from these two extremes. They do not readily dissolve in water 

 containing spirit, and they are insoluble in spirit of 85^ ; they are 

 insoluble in ether, which is only capable of extracting some of the 

 fat which remains mechanically mixed with the crystals. The 

 aqueous solutions exhibit a peach-blossom colour in the case of 



* Physiol. d. Stoffwechsels. Erlangen, 1851, S. 366. 

 t Compt. rend. T. 31, p. 630. 



