SINCE PREYER'S INVESTIGATIONS. 119 



Lancet, 1887, n, 509, 557) has added to our knowledge in this particular 

 by showing a relationship between crystallizability and septic conditions in 

 the body. He found that if a drop of blood were taken from the cleansed 

 finger of a patient who is suffering severely from absorption of the prod- 

 ucts of putrefaction, and that if such drop be placed between a slide and 

 a cover-glass and allowed to remain at room temperature (60 F.), in the 

 course of 20 to 30 hours crystals of reduced hemoglobin of prismatic and 

 needle form will be found, while within some corpuscles little bars and 

 needles may plainly be seen, apparently distinct from the enveloping stroma. 

 He also found that adding putrid blood facilitates crystallization, and that 

 in cases of pernicious anemia crystallizability seemed to be increased. 



The increased crystallizability of human hemoglobin in pernicious 

 anemia that was pointed out by Bond (loc. cit.} was later noted by Cope- 

 mann (Journal of Physiology, 1890, xi, 401), who found that when a drop 

 of blood from the finger of a patient thus affected was allowed to fall on 

 a glass slide, the edge of the drop allowed to dry, and a cover-glass placed 

 on the blood, crystals of hemoglobin gradually formed in from 10 to 48 

 hours. The only exception to this was in the case of patients who had 

 been treated with arsenic for some days, although crystals were obtained 

 upon the discontinuance of the arsenic. 



To imitate the influence of septicemia, as was also shown by Bond, 

 Copemann treated the blood with decomposing serum. This method he 

 found to be successful in the case of the bloods of the bullock, sheep, pig, 

 dog, and cat, but unsuccessful for the blood of man, the monkey, rabbit, 

 and squirrel. Except in the case of man and monkey the crystals were of 

 oxyhemoglobin, and this notwithstanding that the decomposing serum 

 invariably brought reduction of the oxyhemoglobin as it diffused from the 

 corpuscles into the plasma. He states that this occurred to the greatest 

 extent just inside of the edge of the cover-glass, but not extending to the 

 edges where the layer is kept oxidized; and that it is in this intermediate 

 zone of fully reduced hemoglobin that crystals are to be found in the great- 

 est quantity, both in case of human and monkey blood and of that of the 

 rabbit and squirrel; but in the latter the crystals are of oxyhemoglobin, 

 while in the former they are of reduced hemoglobin. He also made the 

 interesting observation that in specimens of squirrel's blood (species not 

 stated) the crystals were in every instance in the form of fine needles and 

 rhombic prisms, the needles sometimes being collected into bundles, while 

 the usual hexagons were absolutely absent. 



Copemann also prepared crystals from the blood of the horse, bullock, 

 sheep, pig, dog, cat, squirrel, rabbit, guinea-pig, rat, mouse, and chicken 

 by the following simple process: The blood is shaken with ether (16 : 1) 

 and then kept under an atmosphere of ether for some time, which may be 

 accomplished by performing the agitation of the blood with ether in a 

 stoppered bottle and gradually allowing the air to escape as the ether is 

 volatilized. By this means the contained air is gradually replaced by ether 

 vapor, while at the same time the small portion of blood which is forced out 

 around the stopper of the bottle on drying fixes it in its place and so prevents 



