Mirrifons for tiik ma\ipi:latio\ of o\'a go 



the total area under a raised coverslip; the CJarrf^I flask; 

 and the watch-glass teehnirjue in which the sterile watch 

 glass containing the culture rnediun^i is contained in a nnoist 

 chamber, iilood plasma or serum ordinarily form the basis 

 of the most successful culture media. I'he longest perirjd of 

 rfigular development of normally fertilized rabbit ova has 

 bef*n obtained by IxnvLs and Gregory (1929j who photo- 

 graphed the development of rabbit ova from the initial 

 cleavage stages through late blastocyst stages. They placed 

 the ova in homologous plasma upon glass slides. Pincus 

 (unpublished data) has obtained similar development by this 

 technique and also with ova grown in Carrel flasks. IxwLs 

 and Ilartman (\iy.V4) observed the development of a Macacus 

 rhesus ov^um from the 2-cell to the 8-cell stage using the 

 Ixwis and Gregory technifjue. The ova of the rat, moase, 

 and guinea pig have failed to de\'elop beyond one or two 

 cleavages with the use of a \'ariety of culture media. I'hus 

 Defrise 0933; used the following media for culturing rat 

 ova: (\) Ringer's solution, bufferr.'d or not with sodium 

 bicarbone; (2) Tyrode's solution, (\) Isotonic with NaCl, 

 milimol: fa) 120, (h) VM), ((■) 151, (B) K+ - Ca^+ - Mg"+ 

 equilibrium on the basis of the triangular diagram of Loewe, 

 milimol: Ta; 2.05 KCL, 1.90 CaCU, 2.20 MgCF,, ^b; 5.63 KCl, 

 3.60 CaCU, 0.52 MgCla: the above solutions were used at 

 pll 6.8, 7.2, 7.6; f3j Tyrode's solution rXaCl: milimol 

 136 - KCl: 5.6 - CaCU: 2.16 - MgCU: 0.52 - XaHC03: 

 8.6 - CJI 1206:5.5) with the addition of gelatine 0.5 per 

 cent; (4) Tyrode's solution (as above) with the addition of 

 blood serum: faj 1/1, fb) 3/1; (o) Tyrode's solution (a.s 

 above) with the addition of plasma (heparin): (a) 1/1, 

 (b) 3/1; (6) pure blood serum of (a) pregnant female, 

 (b) male, (c) newborn; (7) plasma (secured from the heart 

 and mixed with heparin): (a) pregnant female, (b) male; 

 (8) spinal fluid (secured by suboccipital puncture) ; (9) foetal 

 hystolymph (secured by Mart.ino\itch's technique); HO) 

 uterine fluid (II oestral period): (a) pure, (h) with the ad- 

 dition of blood serum. 



