546 



SCIENCE 



[N. S. Vol. XXXIII. No. 849 



Purpose. — -An effort has been made to throw 

 some light upon the relation between B. cholerce 

 siiis and hog cholera. There has also been consid- 

 ered the possibility of a constant relationship be- 

 tween potency of serum and agglutinative power 

 for B. cholerce suis. 



Methods. — The macroscopic, test-tube method 

 has been followed. Cultures were isolated from 

 the spleen of virus hogs. At first a bacterial sus- 

 pension was prepared by washing off surface 

 growth from agar slants with carbol-salt solution, 

 later bouillon cultures were diluted with a solution 

 of formaldehyde. Blood samples were taken from 

 the tail bleedings or at slaughter or death of pigs. 

 Samples of "mixed sera" were preserved in .5 

 per cent, phenol generally. 



Results. — Normal blood serum gave a maximum 

 reaction at a dilution of 1-250 or less. 



Blood of virus pigs gave a maximum reaction 

 at a dilution of 1-800, but usually less. 



Blood of pigs treated by the serum-simultaneous 

 method gave a maximum reaction at a dilution of 

 1-500. These pigs were younger than the virus 

 pigs and, other things being equal, young pigs 

 generally possess a blood of less agglutinative 

 power than old pigs. 



The agglutination reaction appears to be a reac- 

 tion of immunity since, as a rule, pigs treated by 

 the serum-simultaneous method possess a blood of 

 higher agglutinative power if they live (develop 

 immunity) than if they die (fail to develop im- 

 munity). 



During the process of hyperimmunization agglu- 

 tinins for B. cholerce suis increase as the virus 

 injections increase, but not necessarily simultane- 

 ously or in the same degree. 



Of 51 samples of Dorset-Niles serum, only 11 

 gave an agglutination reaction at a maximum of 

 1-1,000 or less, while 7 agglutinated at 1-50,000. 



The agglutinative power of a mixed serum may 

 decrease more or less than 50 per cent, after 6 to 

 8 months in cold storage. 



Potency of serum can not be measured by ag- 

 glutinative power in all cases. 



Sera of high agglutinative power, i. e., agglu- 

 tinating at 1-2,000 or above, were potent in 85.71 

 per cent, of cases and not potent in 14.28 per 

 cent. ; sera of low agglutinative power, i, e., ag- 

 glutinating at 1-1,000 or less, were potent in 45.45 

 per cent, of cases and not potent in 54.54 per cent. 

 Studies on the Filterable Virus of Hog Cholera: 



Chas. T. McClintock, Walter E. King and 



EoBT. H. Wilson. (From the Eesearch Labo- 

 ratories of Parke, Davis and Co., Detroit, Mich.) 



Eesults of experiments indicate that a relatively 

 short residence of hog-cholera serum in the circu- 

 latory system of the horse, in some way causes an 

 activation of the virus. Horse serum, obtained one 

 half to one hour after the animal has received 

 approximately 140 c.e. of hog-cholera virus, is 

 capable of producing more uniform results when 

 injected into healthy hogs than corresponding dilu- 

 tions of hog-cholera serum in normal horse blood, 

 m vitro, and in physiological salt solution. The 

 incubation period following the injection of horse- 

 serum virus is relatively short. 



The minimimi fatal dose of virulent serum, as 

 represented by a dilution of the virus in physi- 

 ological salt solution, does not appear to indicate 

 the minimum fatal dose where the dilution is 

 maintained in the form of horse-serum virus. 



From some analogous phenomena relative to the 

 behavior of toxins, it is suggested that the filter- 

 able virus of hog cholera may contain a distinct 

 toxin portion. 



A Discussion of the Preparation and Distriiution 



of Biologic Products: J. J. Kinyodn. 



Founded upon the experiences of the author 

 who has been intimately connected with the de- 

 velopment in the production of biologic products 

 in the. United States, certain inductions of wide 

 application were drawn pointing toward municipal 

 and governmental manufacture and control. (Sec- 

 retary.) 

 Intestinal Bacteriology: A Resume: Arthtje I. 



Kendall. 



By feeding experimental animals (cats and 

 monkeys) alternately with protein and carbohy- 

 drate, respectively, it is possible to demonstrate 

 definite alternations in the intestinal flora both by 

 staining and by cultural methods. 



These bacterial alternations consist essentially 

 of a definite sequence of proteolytic and fermenta- 

 tive types of organisms. In addition to these 

 changes in the type of the intestinal flora as the 

 diet of the host is alternated, certain bacteria are 

 able to accommodate their metabolism to a protein 

 and a carbohydrate regimen, respectively. For 

 example, B. coli possesses the power of accommo- 

 dating its metabolism both to a protein and to a 

 carbohydrate diet. 



This accommodation of metabolism to dietary 

 changes is a fundamental and extremely important 

 property possessed by many bacteria, and it can 

 be utilized therapeutically. 



