78 THE AMERICAN MONTHLY [April, 



this investigator praises the efiectiveness of fixed alkalies in almost im- 

 perceptible closes in every case of protracted turbidness of a stronger and 

 more of a leuchajmic conditions of human blood. By this he refers to 

 a pathological condition, where there is a decided increase of colorless 

 (white) blood cells, and to the great resistance of the same to the effect 

 of water. I know from experience only the clearing effect of this method 

 in thinning blood whose turbidity is the result of the resistance of the 

 granule conveying red blood corpuscles to the effects of the water. 



The cases for which Mr. Leichtenstein recommends his method are 

 very different from the cases in which I used his method with such ex- 

 cellent results, and I was not as yet in a position to observe the clear- 

 ing effect in the thinning of the leuchaamia human blood. But this b\' 

 no means deters me from unreservedly recommending this method in 

 all such cases of protracted turbidity as have been investigated by Mr. 

 Leichtenstein, and. of course, cases of leuchsemia and leucocythcemia 

 may present themselves to a practising physician. 



There are indeed conditions so simple and so universal that the cer- 

 tainty which the word of a reliable observer gives cannot be increased 

 or diminished by repeated assertions. 



The testing of a definite blood solution is a task of so great precision 

 that in the unanimous reports of all the different universities conduct- 

 ing experiments, the various reports of one or more persons in the same 

 blood test never varied more than one per cent. 



The more deeply the blood solution to be tested is colored, and the 

 thicker, accordingly, that part of the glass wedge which is of the same 

 color, the more light the dull white reflector will throw through the 

 comparing vessel. 



If one is aware that the blood is normal it is best to give the reflector 

 such a position that as much light as possible will be thrown upon the 

 lower surface of the vessel. But in such cases where the thinner parts 

 of the wedge are brought into use, that position of the I'eflector must 

 be sought which supplies a sufficient degree of brightness. 



The universal results from the Hiemometer are, the sharper and more 

 exact the smaller the degree of brightness used in obtaining them. 



The observing eye must be brought at a certain distance, perpendic- 

 ularly over the comparing vessel, the other eye must be closed. It is 

 also recommended to place between the observing eye and the com- 

 paring vessel, tilted upon the latter and standing upright upon the table 

 slab of the Ha^mometer, a cylinder of paper or pasteboard. The length 

 of this cylinder must, of course, be suited to the sight of the observer. 

 It will do no harm to have the inner surface of the cvlinder painted 

 black. The observance of the following rules is of the greatest im- 

 portance : 



The observer should not place himself in a position toward the Has- 

 mometer such as he would, for example, assume in the use of the mi- 

 croscope, but should place himself in the same plane with the partition 

 wall of the comparing vessel. The consequence of this is that the 

 picture of both, according to their color and brightness, with compara- 

 tive exactness semi-circles upon the retina, lie beside each other, not, as 

 in other cases, one upon each other. 



But the comparison of the degrees of brightness is much more exact 

 when the impression is made upon the right and left halves of the 



