•>(;(s; HIROTA : ON TTIR SERO-AMXTOTTr rTjNXErTTOX, 



The eii'g i« then \mt for a few minutes in l\leineiil)erg'« picro- 

 sulphiiric acid in :i cup of moderate size, to partly dissolve and 

 soften the cMlcareous shell. The shell membranes then become 

 easily separable from the allantois, mid the whole contents can he 

 entirely freed from the Jion-cel hilar envelopes. At this stage, the 

 contents being yet soft, a large piece of the shell, disunited from the 

 contents, shcMild be left to suj)port them in their relative positions 

 until they have become hardened in Kleinenberg's fluid. Xext day, 

 the hardening fluid is replaced by ;ilcohol, by taking it away in small 

 portions by a ])ipette from the bottom of the cup, then gently pouring 

 on alcohol (70 ^/o) so that an alcoholic layer rests on it and re])eating 

 this ])i-ocess until it has been entirely replaced by alcohol. \)y this 

 method Kleinenberg's fluid is easily and economically rej)laced by 

 alcohol without disturbing the contents. 



h). Whe?! the egg has been in incuhation mmr tJuni tiro irtuis. There 

 is liere no dangei* of injuring the lilood vessels, for the calcareous 

 shell is now brittle and easily separable from the outer shell -membrane 

 which is white, dry. and leathery. Besides, the contents are now 

 firm and consequently the shell can be taken oif very extensively, 

 and even frimi the entii'e sui-face. Howe\er. the serous envelope 

 being intimately attached to tlie inner shell -membrane, it is almost 

 impossible to separate them in the fresh state witln^ut bleeding. 

 But if we put the whole in Kleineijberg's fluid for ten to thirty 

 minutes, there is no longer anv danger. When, however, we wish to 

 examine the cellular structure of the serous en velo])e, the inner shell- 

 membrane should be left in position, for the safety of the underlying 

 layers. When tlui eontents are thus entirelv cleared from the non- 

 cellulai- envel()|)es, the specimen is put aside in Kleinenberg's fluid for 

 about half;i day. In this case, the contents, being firm the harden- 

 ing fluid (^iin be easilv repinced by alcohol after it has done its \voi"k. 



