886 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is an exceedingly useful staining medium, because it answers all re- 

 quirements in an equally favourable way. It possesses a marked 

 differentiating power, and even surpasses picrocarmine in tbis excel- 

 lent quality. It colours all tissues uniformly, wbetber tbey are fresb 

 or are taken out of alcobol or cbromate of potasb. Wbat is most 

 important is tbat tbe differentiating power is well manifested in 

 botanical preparations, in wbicb eacb tissue takes a special tint. _ Care 

 bowever must be taken tbat tbe sections remain only a few minutes 

 in tbe solution, because it stains witb remarkable intensity. For tbe 

 examination of sieve-tubes (preserved witb so mucb difficulty) Magdala- 

 red will doubtless be very suitable. Tbe vessels of tbe plerom are very 

 clearly distinguished from tbe periblem, &c. Tbe lower fungi also, 

 sucb as Mucor, Penicillium, Aspergillus, &c, also take a beautiful 

 colour, like bistological sections. An exceedingly satisfactory result 

 is likewise obtained witb parasites (mites, worms, &c). A further 

 advantage is tbat tbis dye bas a great capacity of resistance to potasb, 

 and tbus, if required, specimens can be first stained and tben treated 

 witb potasb. For double staining it does not seem to be suitable, as 

 it destroys tbe otber colour. 



Tbe autbor adds, " wbetber it does not possess tbe same disadvan- 

 tage as beematoxylin and otber aniline colours, and disappears from 

 tbe preparation after a time, and is tberefore unstable, I am not yet 

 able to determine." 



Preparing Fossil Foraminifera, Spicules, &c* — In a second 

 paper "j - Mr. C. Elcock gives directions for preparing fossil Fora- 

 minifera. Tbe material from wbicb tbey may be most easily pre- 

 pared is cbalk powder, many ways of doing wbicb are recommended 

 by text-books, but all unsatisfactory in practice. 



Tbe only material wortb bandling from wbicb to obtain tbe 

 Foraminifera found in tbe cbalk in a condition almost, if not quite, 

 uninjured, is tbe powdery matter found in tbe cavities of tbe flints 

 wbicb abound in tbe cbalk, but especially in cavities in tbe large 

 nodules known as " Paramondras " — masses of flint of very irregular . 

 ovoid form in wbicb are cavities of various sizes filled witb cbalk 

 containing Foraminifera, wbicb as a rule are in fine preservation. 



On no account sbould tbe plan be adopted of sbaking up tbe 

 powder witb water in a bottle, wbicb is worse tban useless ; but if it 

 is dry, tbe first tbing is to sift it tbrougb a ratber coarse sieve — zinc 

 perforated witb holes ^ inch in diameter will do — so as to remove all 

 tbe fine flakes of flint, wbicb would cut gauze like lancets. If 

 damp or wet, tbe powder may be washed through tbis zinc sieve under tbe 

 tap into a sieve (9 incbes in diameter and 4 inches deep), with Miller's 

 silk-gauze 180 threads to the inch. Either way will answer well, 

 but after mucb experimenting Mr. Elcock prefers first to dry perfectly 

 and sift dry. What will not pass through tbis zinc sieve must be 

 well and carefully washed, and looked over when dry, as it will contain 



* Journ. Post. Micr. Soc, i. (1882) pp. 139-45. 



f First paper (on recent Foraminifera) loc. cit., pp. 25-9. Of. this Journal, 

 ante, p. 436. 



