

ci TTINQ AKD V"i\ riNO 321 



Btaining w Ith borax- or picro-carmii 



(Zeits. f. wiss. Zool., xliii., L881 Joum I; 



Oct. 188*2 E 



Heir .1. Nusbaum thinks thai one method "t" ; 

 never afford torj material for Btudy, cb metb 



different results. He treated fresb eggs with Kleiuenb 



ayi's fluid, or treated them ;i f< nds witb bo( watei 



then with bichromate of potasb. Tbi in eith< 



hardened in 70 per cenl mid then absolute alcohol ; then colored in 

 /./A- by hematoxylin, borax-carmine, it red magdala ; tin- latter 

 a perfecl Btaining reagent, coloring the i L r u r > and embryos in a few 

 hours, and verj intensely, though sometimes very uniformly.* 



Preparing Embryos of Insects. -In a paper un the embryonic 

 development of the Bombycidae, Dr. S. Selvatico describes the 

 methods he has made use of both for the preparation of entire em- 

 bryos and for sections, The species employed were B mori, 

 i out mylilia, and Salurnia pyri. 



I'h, eggs are firel coagulated by plunging them in water at 75 ' 

 Willi a pair of One-pointed forceps a small piece is ti mov< d from the 

 shell, in Hi' I Bombyx, withoul disturbing the underlying 



parts. With a little care this is easily done, because on th< 

 coming cold, their contents are Bomewhal contracted and do not 

 touch the shell. In thi A.ttacus and Saturnia tl bave 



a harder shell bul arc larger, and a razor was employed bj the 

 author. 



They are then hardened by leaving them for tw< irs in a 



.002 per cenl solution of chromic acid, and for twelve hou 

 in a .006 solution. Then with a little can' the shell can be easily 

 removed by employing the forceps or cutting it round witb a n 



The entire contents having been removed, thi - freed from 



chromic acid in leaving it in 80 per cenl alcohol fi>r a day, the 

 alcohol being renewed until it is no longer colored yell< 



For Btaining, the a r ^ r is placed in picrocarmine for four 



hours and washed in ;'>" per cent alcohol to removi thi 

 Win n it has been \\ ell washed it may be kepi in :'■" pei cenl alcohol 

 until section.-, arc required. 



Previous to cutting sections the egg should be placed iu absolute 



alcohol for hall" an hour, and then for B few nioiiu nts il i ss< u< 



bergamot. Dry and embed in a mixture of 4 pat 

 and 1 of cacao butter, to which is added, accord it tempera- 



ture, some drops of castor-oil. The knife should 1 I with 



* Arch. Zool. Exper., 1887, 124; Joum. Roy. 11 



841. 



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