810 



SCIENCE 



[N. S. Vol. XXV. No. 647 



The brief vitality of many of the cultures 

 of Diplococcivs mtracellularis is a point of 

 differential importance. Many strains, 

 grown in a favorable medium, unless trans- 

 planted to a fresh medium, do not survive 

 beyond two or three days. Cultures three 

 days old show marked degenerations, and 

 the latter increase rapidly with age until, 

 at the end of five or six days, or even 

 earlier, no normal cocci persist. As de- 

 generation progresses, loss of staining 

 power and disintegration ensue, until, 

 finally, staining is lost and a formless de- 

 tritus remains. 



The changes in the diplocoecus are asso- 

 ciated with the action of an enzyme which 

 brings about the disintegration. This 

 enzyme does not exhibit the usual proper- 

 ties of a proteolytic ferment; it does not 

 liquefy gelatin or coagulated serum. The 

 degree and rapidity of its action varies 

 with its concentration; at least a heavy 

 suspension of the cocci in salt solution, kept 

 at 37° C, undergoes dissolution more 

 rapidly and completely than a weaker sus- 

 pension. The vitality of the cultures is 

 associated with the degree of autolytic 

 alterations in the suspensions ; cocci in the 

 weak suspensions survive longer than in the 

 stronger ones. At lower temperatures— 

 2° C— disintegration of the cocci either 

 does not take place at all or progresses 

 much more slowly. Under the latter condi- 

 tions more cocci survive in the strong than 

 in the weak concentrations, although even 

 here the vitality is a brief one. 



Potassium cyanide restrains the action 

 of the ferment which tends to disintegrate 

 the diplococci ; after removal of the cyanide 

 dissolution sets in. Heating the diplococci 

 to 65° C. prevents or reduces the dissolv- 

 ing power of the intracellular enzyme. 



The enzyme acts upon the dead cocci— 

 probably not upon the living germs. 

 Diplococci killed by heat (50° to 55° C.) 

 undergo autolysis; but when the cocci are 



killed by the addition of toluol, autolysis 

 is accelerated. A heavy suspension of the 

 diplococci in salt solution, under toluol kept 

 at 37° C, may be disintegrated in four 

 hours. 



The enzyme of the diplococeus acts ener- 

 getically upon other bacteria, bringing 

 about their dissolution. It acts upon B. 

 typliosis, B. coli communis, B. pyocyaiv- 

 eus, B. anthracis, M. catarrhalis, and to 

 a less degree and more slowly upon Staphy- 

 lococcus aureus. 



The Stability of Tetanus Toxin: M. J. 

 RosENAu, Hygienic Laboratory, Wash- 

 ington, D. C. 



Some Observations on the Blood of Horses: 



J. J. KiNYOUM, Philadelphia, Pa. 



The volume percentage of the cell con- 

 tent of normal horse blood ranges from 30 

 to 46 per cent. ; an average of 37.8 per 

 cent. The administration of diphtheria 

 toxin, causes a diminution of the red cells 

 to an average of 30 per cent. 



The anaemias induced by the toxin and 

 the subsequent bleedings are progressive, 

 and are in direct relation to the length of 

 treatment. Horses treated with tetanus 

 toxin, or with dead or living micro-organ- 

 isms, also show a progressive diminution of 

 the corpuscular content, but it is not so 

 great as in the cases when diphtheria toxin 

 is administered. 



The danger point for all horses, beyond 

 which the horse can not be bled, is when the 

 cell content falls below 20 per cent. The 

 leucocytes bear no fixed relation to the red 

 cells; it may be as great as 1 per cent, or 

 as small as 0.1 per cent, normal, and the 

 same in those undergoing treatment. 



There is also no relation between the cell 

 content and the anti-bodies. 



The haemoglobin follows very closely the 

 curve of the cells (red), both in the normal 

 and in the treated horses. 



Toxic Effects of Horse Serum.— Guinear 



