460 im. J. L. CTjAEKE on the geet shestance of the spinal coed. 
ceed with him ; “ the preparation became only partially clear, and the gangliomc ceU^. 
from which the fat seemed to be removed, were rendered indistmct*. It is perfec ; 
clear that he had not sufficient practice in the process. He says agam m speakmg o 
LehhossSk, “ he follows Claeke’s method with turpentine, which, according to my ejyc- 
rience, cannot lead to conect results, as the spinal marrow is too much ahered by t at 
aeentt ” After criticising every other method, he describes his own, which consists in 
the use of concentrated chloride of calcium, and which, according to his expenence 
“ deseiwes to be preferr ed to all the others.” But now we find that he has abandoned 
it and adopted my method in conjunction with the colouring process recommended by 
Geelach; for in a supplementai-y paragraph to the English translation whic as pis 
been issued by the Sydenham Society (1859), he states that after some tnals he finds 
this mode of making preparations the most satisfactory, and in many respects stul bettei 
than with chlonde of calcium. The section, after having been coloured with solu mn 
of carmine and washed in spirit, is laid in a watch-glass and aUowed to diy a 
after which, “a couple of drops of spirit of turpentine are added If it is now e 
for twenty-four or forty-eight hours without a covering glass, but protected from the 
dust, the spirit evaporates, and the object becomes perfectly clear. It is now coveie 
with Canada balsam and a glassj.” The colouring with carmine is often very useful, 
but I think it rather interferes with the sharpness of the fibres. I ha^i e long used, occa 
sionally, a colouring fluid known to painters and wood-stamers by the name of aic ie . 
When carmine is used, the solution should be previously Altered, otherwise a deposit or 
crust is apt to form on the object; and for the same reason, the section, aftei having 
been coloured, should be washed in water before it is placed m the spmt, which leadily 
precipitates the carmine. , . . 
Stilling has given a full, but somewhat inconsistent and mcorrect criticism on my 
method. He concludes by saying, “While it is allowed that by the employment of 
Claeke’s method many truths indeed in reference to the minute structure of the spinal 
cord may be brought to light, and that Claeke’s labours must be said to be quite trust- 
worthy (recht anerkennenswerthe), it must nevertheless be observed that the condition 
of certain textures, such as the elementary structm-e of the primitive nerve-fibres am 
the nei-ve-cells, are so altered by it, that this method in many respects must be con- 
sidered as an obstacle to the more exact kind of investigation 
Now although I am not so blindly prejudiced as to niaintam that preparations nm e 
by this method ai'e in eveiy respect perfect, I do maintain that it produces but litt e 
alteration from the natural appearance of the nerve-cells, and that almost the on y 
structure that appears to suffer more than from chromic acid alone is the white sub- 
stance of the neiwe-fibre; and even this may be perfectly preserved if the medulla is 
placed first in a weak solution of chromic acid and then in a solution which is niuci 
Stronger. Fig. 1, Plate XIX. was drawn from a preparation made in tins way, and ot 
* Translation of Sydenham Society, 1859, p. 30. 
t Loc. cit. p. 33. 
t Ibid. p. 28. 
§ Neue TJntersucb., 5 Lief. p. 1071. 
