1896.] MICROSCOPICAL JOURNAL 401 



as less oxyg-eii is required than for vertebrates. The fix- 

 ing- fluid must be cooled on ice before placing- the tissue 

 in it. After remaining- in the cold fixing- fluid for from 2-4 

 hours the tissue is thoroughly washed with cold water, 

 which g-enerally takes about two hours althoug-h it has 

 been continued for twelve hours without injury. 



It is necessary to remove all the molybdate of ammonia 

 by thorough washing- if permanent preparations are to be 

 secured. 



The tissue is then passed rapidly, ten to fifteen minutes 

 in each, through the ordinary grades of alcohol to absolute, 

 all being- kept cold with ice. The tissue should be left in 

 the absolute alcohol for about two hours at a freezing- tem- 

 perature and the alcohol be changed several times. The stain 

 is dissolved by dilute alcohol at ordinary temperatures. 



Dr. Ruber's plan of placing- the tissue directly in cold 

 absolute alcohol on removing- it from the water and chang-- 

 ing- several times for a period of two hours, g-ave good re- 

 sults. 



After thoroug-h dehydration the tissue is placed in xylol 

 for 12-24 hours and chang-ed several times. It is then im- 

 bedded in parafline in the usual way. 



The most complete and in every way satisfactory stain- 

 ing- of the sensory nervous system was obtained by two or 

 three injections of a )^ per cent solution of Erlich's methy- 

 len blue at intervals of from 15 'to 20 minutes, both with 

 vertebrates and invertebrates, as sug-g-ested by Semi 

 Meyer. 



[^.'The tissues relaxed after the first injection, so that more 

 fluid was introduced by the second and third injections 

 than by the first. 



The use of chloroform was found to be wholly unneces- 

 sary by this method. Meyer uses a very strong- solution of 

 B. X. methylen blue, 5 per cent to 6 per cent, in water. 



The parafline sections should g-enerally be quite thick 

 (45-60 mm.) — The American Naturalist. 



Blood Stains.— Blood stains may be removed from the 

 hands by the use of tartaric acid. 



