136 On the Value of High Powers 



wliicli my friend, Prof. Theodore G. Wormley, M.D., of Columbus, 

 Ohio, kindly permits me to mention here, but which may appear 

 more in detail in his appendix on blood stains to the next edition 

 of his splendid work on ' Micro-Chemistry of Poisons.' During a 

 recent visit to Philadelphia Prof. Wormley brought with him a 

 slide of human blood, upon which were seven corpuscles (designated 

 by numbers on an accompanying drawing), which he had measured 

 under several different objectives and forms of apparatus. These 

 corpuscles Dr. W. requested me to measure under my ^V immersion 

 lens, and after doing so I found that my results agreed very closely 

 with his own, and that in two or three instances they were precisely 

 identical. The mean diameter of the seven disks, according to my 

 computation, was ^i^-^ against ^sVe^ o^ ^"^ i^^ch, the average of his 

 measurements. There was thus a total deviation from the true size 

 of only ^"s^oVir^^ of an inch in my results, which were those of an 

 independent observer, seeing the objects for the first time, and 

 determining their magnitude under a magnifying power, and by 

 the aid of apparatus entirely different from those Prof. Wormley 

 had employed. 



Thirdly, the assertion of Virchow, that a man's hfe should not 

 be put in question on the uncertain calculation of a blood-corpuscle's 

 ratio of contraction by drying, does not seem to me a fair statement 

 of the point at issue ; because since the red blood-corpuscles of 

 oxen, horses, pigs, sheep, deer, and goats are all much smaller than 

 those of man, no degree of contraction which they could undergo 

 would render the stains in which they occur more liable to be 

 mistaken for man's blood ; and if, as is rarely, if ever, the case, 

 human red blood-corpuscles in a stain were by any means contracted 

 so as to resemble those of an ox, for instance, in size, the evidence 

 from microscopic examination would only mislead us into assisting 

 in the acquittal of a criminal, and could not betray us into aiding 

 to convict an innocent person. 



Had Prof. Virchow worded his statement so as to read, " the 

 uncertain 'calculation of a blood-corpuscle's ratio of contraction or 

 expansion by drying," his objection would have been strictly logical, 

 although, as I believe, it would not have been founded upon fact, 

 because if a corpuscle of ox blood could expand during the process 

 of desiccation or of moistening so as to even approximate to the 

 human red disk in magnitude, it might mislead us into testifying 

 erroneously to the presence of man's blood, when beef blood alone 

 had been shed, and thereby endangering the life of an individual 

 who was entirely guiltless. 



But my observations, made upon many different kinds of blood, 

 and under a great variety of conditions, clearly indicate that the cell- 

 wall of a red blood-globule is nearly or quite inelastic, and incapable 

 of any marked expansion by the process of drying or moistening 



