1886.] MICROSCOPICAL JOURNAL 401 



as less oxygfen 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 thoroug-hly washed with cold water, 

 which g-enerally takes about two hours although it has 

 been continued for twelve hours without injury. 



It is necessary to remove all the molybdate of ammonia 

 by thoroug-h washing- if permanent preparations are to be 

 secured. 



The tissue is then passed rapidly, ten to fifteen minutes 

 in each, throug-h the ordinary g-rades 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 chang-ed several tim es. 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 >2 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. 



[Z. The tissues relaxed after the fi^rst 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 paraffine 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. 



