MOIORAXDA. 



271 



infinitesimally minute " marvels of the microscope " the 

 better it will be for them if they are spared to enter those 

 years of senility to which, I regret to say, I am rapidly 

 approaching ; or, in vulgar speech, you'll smart for it if you 

 live to be old fellows. — Henry U. Janson, Pennsylvania 

 Park, Exeter. 



Composition of a Blue Transparent Injecting Fluid for Anato- 

 mical and Pathological Preparations —Not having been very 

 fortunate in preserving microscopic injections of tissues made 

 with the very beautiful blue fluid recommended for the pur- 

 pose by Dr. Lionel Beale,* I was induced, in conjunction 

 with Professor Barker, of Dublin, to endeavour to discover a 

 blue fluid of a less fugitive disposition than the one 

 alluded to. 



Having performed many experiments with different inject- 

 ing fluids, we found that tissues injected with a colour of the 

 same chemical composition as Turnbull's blue, are not so 

 liable to fade as those injected with the Prussian blue. 



When ferridcyanide of potassium is added to a salt of the 

 protoxide of iron, a beautiful blue precipitate is the result. 

 It is somewhat brighter in tint than Prussian blue, and its 

 colour is unexceptionable. 



Having been very successful in preserving preparations made 

 with this blue, we thought we should not lose any time in 

 mentioning the proportions we found to answer best for 

 making a free-running injection. 



Composition of the blue fluid : 



Purified sulphate of iron ... 10 grs. 



Ferridcyanide of potassium . . . 32 „ 



Glycerine (Price's) . . . . 1 oz. 



Wood naphtha or pyro- acetic spirit . 1^ drachm. 



Spirits of wine . . . . . 1 oz. 



Water ...... 4 „ 



Dissolve the sulphate of iron in one ounce of the water, and 

 the ferridcyanide of potassium in another ounce, then gra- 

 dually mix the two solutions in a large bottle, shaking well 

 during the mixture. Next add the naphtha to the spirit, the 

 glycerine, and the remainder of the water. Finally, add this 

 mixture to the Turnbull's blue, and again shake well while 

 they are mixing. 



Those familiar with Dr. Beale's fluid will perceive that the 

 difference between it and the one we recommend only con- 



* 'How to Work with the Microscope/ p. 78. 



