ADDITIONS AND NOTES TO VOL. II. 527 



these calculations, besides the exact counting of the corpuscles in 

 each analysis, it is necessary to assume one, if not two, probable 

 magnitudes. 



If we abstain from entering more fully into this subject, and 

 for the present withhold our judgment on a question of physio- 

 logical chemistry which promises to be of the highest importance 

 to physiology generally, this does not arise from a want of appre- 

 ciation of the great merits of Vierordt in this department of 

 chemistry, but simply because we do not regard a manual of this 

 kind as a suitable place for the introduction of investigations of 

 this nature, and because we have been anxious, as far as possible^ 

 to base our judgment solely upon our own experiments and upon 

 post mortem examinations. In consequence of the different direc- 

 tion of our own investigations regarding the blood, we are hardly 

 in a position to criticise in their individual details the labours of 

 Vierordt. Such a critical and experimental testing is, however, 

 indispensably necessary before we can form a correct judgment 

 of this method, as a number of considerations force themselves 

 upon our notice, which, although they have in part been explained 

 by Vierordt himself, are still sufficiently numerous to demand an 

 experimental examination. O. Funke,* among others, has shown 

 with much clearness the possible causes of error which appertain 

 to this method. For the present, we may regard Schmidt's 

 method of blood-analysis, of which we have considerable experi- 

 mental knowledge, as the one which, notwithstanding some well- 

 known deficiencies, affords the most certain results. 



(24) Addition to p. 227, line 19. Vierordt f found in his 

 various countings that in 1 cubic millimetre [the linear millimetre 

 being about l-25th of an inch] of normal blood obtained by 

 pricking the finger, there are on an average 5,055,000 blood- 

 corpuscles ; Welker,J on the other hand, fixes the number at 

 4,600,000. 



(25) Note to p. 237, 7 lines from the bottom. [The view 

 stated in the text, that the colourless were to the red corpuscles in 

 the ratio of 1 : 8 or 1 : 10, is now exploded; Henle makes the 

 ratio as 1 : 80 ; Bonders and Moleschott subsequently showed 

 that 1 : 373 was about the average ratio. Moleschott has re- 



* Schmidt's Jahrb. d. ges. Med. Bd. 74, S. 1-7, and Bd. 78, S. 5-9. 

 t Arch. f. physiol, Heilk. Bd. 11, S. 867-874. 

 % Fechner's Centrabl. 1853. No. 12, S. 22. 

 Wien. med. Wochenschr. No. 8. 1854. 



