SECT. 6] 



OF THE EMBRYO 



857 



more acid than the yolk, though neither is as far from the neutral 

 point as at the beginning. As for the allantoic liquid, Aggazzotti did 

 not collect many figures for it, but its pH seemed to follow a curve 

 convex to the abscissa, but always near neutrality, while that of the 

 amniotic fluid wavered around neutrality until the nth day, after 



o White, Aggazzobti 



a White, Vladimirov 



A White (fchick),Baytendijk 



V White (thm), „ 



O White,Healygj Peter 



White,Gue_ylard^Portier 



O All., .= " » 



• Yolk, Aggazzotti 

 ■ Yolk,Buytendijk 



♦ Yolk,Healy8j Peter 



* YoikjGuej/lard^Portier 

 ® Amniotic f laidjAggeizzotti 

 B »> 5> ,Bayfcend(jk 

 o Al^Aggazzotti <^> 



O 



Days 



12 3 4 



J 1 L 



5 6 



L 



I 72 I 120 I 168 I 



9 10 11 12 1314 15 16 17 1819 '20 21 

 J \ 1 \ i 1 \ 1 1 1 1 \ L 



I 312 I 360 1 408 I 456 I 



24 I 72 I 120 I 168 I 216 | 264 I 312 I 360 I 408 I 456 I 504 

 48 96 144 192 240 288 336 384 432 480 

 Hoars 

 Fig. 211. 



which it plunged rather suddenly into the acid region. Fig. 2 1 2, which 

 shows the total acidity expressed in c.c. of JV/ioo H2SO4 or NaOH 

 required to neutralise to a-naphtholphthalein i c.c. of yolk or 

 white diluted to 3 c.c. with i per cent, sodium chloride solution, 

 gives a very similar picture. Just as the pH of the yolk rises 

 during incubation, so there appears to be less free acid there, 

 and just as the p¥L of the white falls, so there is more free acid 



