118 Dr.8.B.Schryver. Some Investigations Dealing [Aug. 12, 
place, however, after the addition of acids; this addition must not, however, 
exceed that necessary to produce a turbidity in the peptone solution 
(precipitation of nucleo-protein). The precipitation is also inhibited by 
the sodium salts of weak acids. This is due to the fact that the solution, 
after the addition of aldehydes, contains acids of the type CH: N-R-COOH, 
which are sufficiently strong to decompose the sodium salts of weak 
acids. For this reason, salts of weak acids, such as sodium acetate and 
sodium propionate, do not fall in the same relative position with regard to 
their inhibitory action as would be expected from the theory connecting 
viscosity and surface tension with this function. 
explain other minor deviations shown in the accompanying table. 
In these experiments, of which the results are here recorded, 5 cc. of 
a Witte peptone solution were diluted to 10 cc. with varying quantities of 
normal solutions of different salts, so that a series of solutions of 24 per cent. 
peptone in concentrations varying from N/10 to N/2 of the different salts 
was obtained. To each dilution was added 2°5 c.c. of a 35-per-cent. 
formaldehyde solution. 
intervals was then noted. 
This fact may serve to 
The degree of precipitate formation at varying 
Table giving Inhibitory Action of Various Salts on the Formation of 
Poly-methyleneimino-peptone. 
O indicates no precipitate. 3 indicates marked opalescence. 
if * faint turbidity. 4: . quite opaque mixture. 
2 3 opalescence. 5 * precipitate formation. 
The three numbers under each heading indicate the observations after respectively 23, 42, 
and 20 hours. 
| | 
Concentrations. | SN 4N 3N 2N : aI : 
| | 10 10 10 10 10 
Sodium chloride ............. 8 34°65.) 3943-555 |.4 4 6 | “b= .59 soUpomromee 
Jp MOLOMIGEe! = acta 0 0 0; O O O};-1 —-1 +8) 444 5/5 5 5 
ee ae DIGT ALC...) ome 0 0 OO} 0 O Oj]-1 —1 +8)4+8 4 65/55 5 5 
| ath | MOGICG! v.. a secre ese 0 0 0} 0 6 O|} 0 O OF 8 4 4.058 oee5 
5  Ssulphocyanide...... | O° O OF; VOrsOrred | 2° 2 3S | 45 74 Oo Pougomes 
uy) @tOrimates: neater: 0 O Oj-1 —1i 1 Sua outs 5 99, — 
| ee IACtAbO era eree tone. Teed ed! es eee cle A Al) Aan eee — 
ise WACOLALE Fan ayer e ec Oo O O OO LEO 0 O-Il1 4 4 +4 — 
», monochloracetate 0 oO-1 2 nO 3 +3 £5 5 6. 5 | Oat 
»  dichloracetate ...... OF, 0 0 QO) BOM 2 93 65 5 6.5 | 5 855 
»  trichloracetate...... — 0 0 O Bid od Ceveobae 4 4 65 | 6p 5a5 
*,  benzoaternst 1352.) — 0.) 70). 0r|, .0°.-0.- 0.) On, 0, (0 See 
Seine LSGLICY IabOn meee ce .,c — 0 oO O 0 oO O 1° 1 1 | Saas 
oP malonate... _ a 0 0 0O| 0 0 0 )\0eme 
st PUSUCCIMALe sR oun — | — = —— 0 0-0 
alin banbrate vee tac. x sc! — | oO O Oj—1 -—-1 -1 4 4 415 555 
pea Uicitrater tl 7.265. it — | — 0 oO O 0 710) OAHOP OF 8 
’ 
