218 



SCIENTIFIC AGRICULTURK 



March. 1922. 



(c) six strains are Gram negative rods; 

 three strains ferment glucose and lactose 

 to acid and gas and liquefy gelatin ; two 

 ferment glucose and lactose to acid and 

 gas but fail to liquefy gelatin; one fer- 

 ments glucose to acid, has no action on 

 lactose and liquefies gelatin. 



The features of the eleven cultures in 

 Group II — the cultures which produce a 

 stratiform dissolving in milk — are as 

 follows : — 



(a) nine strains are Gram positive cocci 

 fermenting glucose and lactose to acid, and 

 liquefying gelatin. 



(b) two strains are Gram positive rods 

 which ferment glucose to acid, have no ef- 

 fect on lactose, and liquefy gelatin. 



The features of the seventeen cultures in 

 Group III are as follows : — 



(a) eight strains are Gram positive rods; 

 four strains ferment glucose and lactose to 

 acid and liquefy gelatin ; three ferment 

 glucose to acid, have no action on lactose 

 and fail to liquefy gelatin; and one fer- 

 ments glucose to acid, produces slight 

 acidity, and later alkalinity in lactose, 

 and liquefies gelatin. 



(b) three strains are Gram negative 

 rods : two strains ferment glucose to acid, 

 have no action on lact^ose, and liquefy ge- 

 latin ; one ferments glucose and lactose to 

 acid and gas but fails to liquefy gelatin. 



(c) four strains are Gram positive cocci: 

 three strains ferment , glucose and lactose 

 to acid and liquefy gelatin ; - one ferments 

 glucose to acid, but fails to a'tack lactose 

 and fails to liquefy gelatin. 



(d) two strains are Gram negative cocci: 

 one strain ferments glucose and lactose to 

 acid and fails to liquefy gelatin ; one fer- 

 ments glucose to acid, fails to ferment 

 lactose and liquefies gelatin. 



The features of the eighteen cultures in 

 Group IV are as follows : — 



(a) fourteen strains are Gram positive 

 cocci, fermenting glucose to acid, and with 

 one exception fermenting lactose to acid; 

 all liquefy gelatin. 



(b) two strains are Gram positive rods: 

 one strain ferments glucose and lactose to 

 •acid and ga.s and licpiefies gelatin; one fer- 

 ments glucose to acid, fails to ferment 

 lactose, but liquefies gelatin. 



(c) two strains are Gram negative rods 

 which ferment glucose and lactose to acid 

 and gas; one strain only liciuefies gelatin. 

 — See Table II, page 219. 



Note. — Chromogenesis — on agar after 14 

 days incubation at room temperature. The 

 chromogenesis of the Gram positive cocci 

 has been determined, using the Winslows 

 colour chart. (28) Nineteen of the strains 

 in Group la, eight of the strains in Group 

 Ila, three of the strains in Group IIIc, 

 and eleven of the strains in IVa, are re- 

 corded as Staphylococci (29). One strain 

 in Group IVa is a Micrococcus (29. The 

 remaining six of the forty-eight strains of 

 Gram positive cocci failed to grow at this 

 time. 



Observations on Cultural Studies. 



From the. data recorded, it is evident 

 that in this investigation, the most common 

 type of organism responsible for the "dis- 

 solving" or "peptonizing" of milk is a 

 Gram positive staphylococcus which fer- 

 ments glucose and lactose to acid and 

 liquefies gelatin. This statement must 

 be qualified by a reminder of the fact 

 that the work was qualitative, and that 

 only seventy-eight of our original one 

 hundred and thirty-three strains are in- 

 cluded in the cultural determinations. It 

 will be observed, however, that forty of 

 the strains examined are of the type in- 

 dicated immediately above — see Table II, 

 page 219 and note on Chromogenesis. Not 

 the least interes'^ing feature of the work is 

 the finding that twenty-five of the forty 

 strains have been isolated from milk pro- 

 cured under aseptic conditions — the taking 

 of adequate precautions against contamina- 

 tion from external sources. As our studies 

 are not specifically concerned with the 

 flora of the udder, we have not deemed it 

 necessary to include in the paper the gen- 

 eral results of our examinations of the 

 milk of individual cows, but in our search 

 for the dissolving organisms we have ac- 

 quired laboratory records of the flora of 

 the individual milks examined. And it is 

 worthy of note that the "milk-dissolving" 

 staphylococci include strains isolated from 

 the milk of each of the eleven cows refer- 

 red to on page 216. It would seem legitim- 

 ate to suggest that the occurrence of these 

 staphylococci is in harmony with the find- 

 ings of researches primarily concerned 

 with the bacterial flora of the iu)rmal ud- 

 der of the cow. Bergey, (5) Conn, Esten 

 and Stocking, (6) Harrison and Savage, 

 (4) Harding & Wilson. (7) and Evans, 

 (8). 



