114 DR. J. BRAXTON HICKS. 



was originally made to work its highest marvels. Amateurs 

 desirous, therefore, of effecting all that the optician desires 

 to be accomplished, should urge him to supply the proper 

 kind of glass cover for which the objective was made. The 

 screw collar is but a rough compensation, at the best, for a 

 variable thickness of glass w^hen the instrument is pressed 

 into extraordinary degrees of amplification, such as 5^00 

 diameters for Powell and Lcaland's new immersion one- 

 eighth objective. 



There is still a wide field of research open to amateurs 

 and opticians in using other immersion fluids besides water, 

 — a subject upon which the writer has been engaged for souie 

 time past. 



Observations on Pathological Changes in the Red 

 Blood-corpuscle. By J. Braxton Hicks, M.D. Loud., 

 F.R.S., &c. (With Plate VIII.) 



The numerous observations which have been made within 

 the last ten or twelve years by the means of reagents have 

 done much to elucidate the construction and composition of 

 the red corpuscle of the blood ; but it has struck me, as pro- 

 bably it has done others, that these observations fail to satisfy 

 the cravings of the vital pathologist, inasmuch as most of the 

 reagents employed are not of a kind to be found in the body, 

 or likely to come into contact with the corpuscle in the living 

 subject ; nor could the physiologist derive any satisfactory 

 information from the effect of these kinds of experiments, 

 because they were diverse from anything likely to be found 

 in the healthy body, so that he could not argue from the 

 effects produced to the ordinary healthy processes. I mean he 

 could not, by them, presume to explain the growth or mode 

 of origin of the red globule — the relationship between it and 

 the Avhite corpuscle or leucocyte. The rapidity of the change 

 which takes place in the blood on leaving the body has 

 always hindered the satisfactory observations which were 

 needful. Some of this difficulty has been overcome by the 

 moist and Avarin stages, as also by the electrical chambers, 

 whereby vitality and activity are prolonged. 



The results of the application of reagents, however, have 

 only supplied us with information upon cadaveric changes. 

 In the living animal, if we except Cohnheim's discovery of 



