16 CONCERNING THE RULES AND APPLIANCES 



the cover to become wet. It is also necessary to avoid any 

 approach to a stronger current in laying on the cover-glass just as 

 one would reasonably regard the course of an unexpected current. 



In the examination of human blood, notwithstanding the con- 

 siderable quantity added, it is only on very rare occasions that 

 merely and imperfect dissolution of the elements contained in the 

 blood takes place, and in consequence of which there is a certain 

 turbidness of the liquid, so that a physician in his practice will 

 scarcely ever find himself disturbed by this annoyance. On the 

 contrary, in the examination of animal blood, where red blood 

 cells sometimes carry granules, one must be all the better 

 prepared for an imperfect solution and a persistent turbidness in 

 the water. In all such cases the rule of Mr. Leichtenstein is to 

 add a minimum quantity of caustic alkali. This is an excellent 

 rule. Indeed, this investigator praises the effectiveness of fixed 

 alkalies in almost imperceptible doses in every case of protracted 

 turbidness of a stronger and more of a leuchaemic conditions of 

 human blood. By this he refers to a pathological condition, 

 where there is a decided increase of colourless (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 this method with 

 such excellent results, and I was not as yet in a position to observe 

 the clearing effect in the thinning of the leuchaemia human blood. 

 But this by 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 

 leuchaemia and leucocythsemia may present themselves to a 

 practising physician. 



There are indeed conditions so simple and so universal that 

 the certainty which the word of a reUable 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 



