1885.] 



MICROSCOPICAL JOURNAL. 



129 



them and record, and we would then 

 compare our respective residts. 



For present purposes we may con- 

 fine our attention to the comparison 

 of the measurements of human and 

 dog's blood, althoui^h I am far from 

 confident that dog's blood is that most 

 likely to be mistaken for human. Not 

 to weary the reader with voluminous 

 tables, the result is summarized as fol- 

 lows by giving the maximum, mini- 

 mum, and average measurements in 

 each specimen, taking in every case 

 the specimens giving the largest and 

 the smallest average, also the average 

 of these two. and the average of all 

 of that kind. The measurements are 

 given in terms of the eye-piece micro- 

 meter used. 



Who could reasonabl}- doubt that the 

 blood on that axe-bit was human blood 

 instead of dog's blood, if it was either.^ 

 . This diflerence between the meas- 

 urements of human and dog's blood 

 may seem to some supercautious per- 

 sons to be a very small basis on which 

 to rest a conclusion from which such 

 important results as the decision of a 

 capital case may ensue. But such a 

 diflerence, if found to be constant, is 

 more certain and reliable than the 

 identification of a person by the fea- 

 tures or clothing simply ; and is it 

 ever objected that because persons are 

 constantly being misidentified because 

 of chance resemblance of their faces, 

 persons, or clothing to those of other 

 persons, therefore such evidence of 

 identit}% when oftered, shall not be 

 received and given its due weight.^ 



Probably the cases of doubtful 

 identity are few where a conscien- 

 tious witness would" testify that he 

 could identify the party in question 

 by his features alone with absolute 



certainty or beyond the possibility of 

 a doubt ; but he might \c\y properly 

 claim to do so beyond a reasonable 

 doubt, and this is all the honest mi- 

 croscopist will ever claim for his iden- 

 tification of blood. 



I am, however, while aware of the 

 difficulties which encompass the mat- 

 ter, and with a full sense of the mo- 

 mentous results to be aflected, con- 

 vinced, after the investigations detailed 

 and the examination , of the subject, 

 that the careful and skillful micro- 

 scopist may, after some experience, 

 justly claim so much of certainty for 

 his determination that it is beyond a ' 

 reasonable doubt of correctness. 



Provisional Key to the Classifica- 

 tion of Algae of Fresh Water. — 

 III. 



\_Co7tti)iued from page 114-^ 

 II. ORDER SIPHONE/E Kirchner. 



Vegetative thallus composed of a 

 single, anastomosing, tubular or blad- 

 der-like, comparatively large cell ; the 

 upper part, growing in air or water, 

 produces chlorophyll, the lower part a 

 colorless, often much bi'anched, hair- 

 root. 



[A large order, with only two 

 genera represented in fresh water. 

 The strictly unicellular nature of the 

 fronds is not in all cases constant 

 throughout the life of every species, 

 l)ut it appears to continue in every 

 case until the reproductive process is 

 about to begin.] 



FAMILIES. 

 Plant terrestrial, spherical, green, 

 with branching, subterranean rhi- 



zoid. BoTRYDIACEvE, IV. 



Thallus filamentous, green, branch- 

 ing. Vaucheriace^, V. 



Family IV. Botrydiace^. 



Thallus terrestrial ; composed of 

 an aerial green part, and a subter- 

 ranean, colorless, branching, root-like 

 part. 



Propagation by copulation of swarm- 

 spores giving rise to a zygospore, from 

 which a new vegetative plant grows. 



