1885.] 



MICEOSCOPICAL JOURNAL. 



127 



voluntary mutilation can subserve it 

 not easy to conjecture, and why 

 ga 



IS 



the suctorial organs are not with- 

 drawn and this waste of substance 

 prevented it is equally difficult to 

 imagine. Can the infusorian be with- 

 out the ability to entirely withdraw 

 the tentacles when once extruded ? 

 The suggestion seems plausible, and, 

 indeed. I have not yet observed an 

 individual without some trace of 

 these organs protruding from the sur- 

 face. In several instances tentacles 

 have been partially withdrawn, and 

 the extremity of the crowded exter- 

 nal spirals of sarcode below the capi- 

 tate bulb have become divided into 

 numerous long, fine, vibratile fila- 

 ments, as shown on two tentacles in 

 fig. lo. This formation has been 

 observed only after the infusorian has 

 been in confinement for a considerable 

 period. It is therefore probably an 

 evidence of discomfort or a symptom 

 of pathological change. Two ten- 

 tacles on the same individual have 

 been seen in this condition, but the 

 infusorian did not appear to be weak- 

 ened or ill at ease, as the remaining 

 ones were fully extended, or actively 

 withdrawn and protruded. The ap- 

 , pearance has not been previously ob- 

 served, and it needs an explanation 

 which is indeed difficult to make. 

 Trenton, N. J. 



The Microscopical Discrimination 

 of Blood.* 



BY C. M. VORCE, F. R. M. S. 



After what has already been writ- 

 ten on this subject (vol. iv, p. 223, 

 vol. V, p. 17) it is now desirable to 

 detail some practical applications of 

 the facts recited. By many persons 

 the subject is treated as if it were a 

 matter of great and natural difficulty, 

 w^hile the fact is there is no other in- 

 herent difficulty than the necessity of 

 care and the choice of proper methods. 

 x\s the result of considerable experi- 



*This article was originally written in the fall of 

 1884 .<■. a conclusion of the author's previous articles 

 on the subject, but, being withheld for revision, was 

 mislaid, and for a time lost. 



ence, I consider that the practical re- 

 quisites for accurate measurements of 

 blood corpuscles and the examination 

 of blood stains are : — 



1 . Homogeneous immersion ob- 

 jectives of powers J to jV or upwards 

 with good working distance. The 

 objectives should be non-adjustable, 

 or else the adjustment should be fas- 

 tened so as to be incapable of move- 

 ment after being once correctly ad- 

 justed. 



2. Eye-piece and tube-length to 

 give 1 ,000 to 1 ,500 diameters or up- 

 wards. 



3. Eye-piece micrometer to give 

 measurements to -gxri¥Tr "^ch or finer. 



4. Fine adjustment to move body 

 and not nose-piece. 



5. Mechanical stage and good sub- 

 stage achromatic condenser. 



6. A quiet work-room, free from 

 noise or tremor. 



The methods of treatment may be 

 various, but all comparisons should 

 be by absolutely the same method. 



It may prove of interest to describe 

 some methods chosen from actual 

 experience, and the results obtained 

 thereby. For this purpose the pi^o- 

 cesses followed and results obtained 

 in an investigation undertaken at the 

 request of the authorities in one of the 

 interior counties of Ohio, in a murder 

 case lately tried there, will be briefly 

 given. 



In the case in question certain 

 blood stains on wood, steel, felt, cot- 

 ton cloth and woollen cloth were 

 submitted for examination, with a 

 view of determining whether stains 

 of human blood could be distinguished 

 from stains of the blood of other ani- 

 mals, especially the dog. The stains 

 were upon the hat and clothing of the 

 accused person, and upon the bit and 

 helve of an axe found on his premises. 

 As to the stains on the prisoner's 

 clothing, he accounted for them by 

 claiming that he had suffered with 

 bleeding at the nose on the night in 

 question ; as to the axe he professed 

 entire ignorance. 



The examination was conducted in 



