1010] 



VETERINARY MEDICINE. 83 



ii is the process of flocculation and Dot thai of the union of antigen with anti- 

 body which Is thus Inhibited. 



In the discussion of the second phase of the agglutination test, the demon- 

 stration of the formation of a complex hy its flocculation, the following points 

 are considered: (1) Intluence of the reaction of the suspending fluid in which 

 the interacting bodies are dispersed, upon the process of flocculation, and in- 

 tluence of the valency of the electrolytes upon the process in presence of acid 

 and alkali. Experiments are reported which show that hydroxid ion interferes 

 with the process of flocculation, a relatively small concentration having a 

 marked inhibitory effect. If replaceahle hydrogen ion be present, this inhibi- 

 tory effect is negatived. (2) The relation which exists between the degree of 

 sensitization and the precipitating value of the electrolytes present in the 

 menstruum: An organism can form, along with its own antibody, a variety 

 of complexes differing inter se in their susceptibility to flocculation. These 

 complexes are probably not different in kind but only in degree. (3) Effect 

 of other physical factors upon the second phase of agglutination: The surface 

 tension and viscosity of the menstruum have been found to have little effect 

 on flocculation. The temperature affects the flocculation by producing a con- 

 tinuous movement of the interacting bodies in the suspension and by encour- 

 aging or inhibiting, owing to its altering the physical state of certain com- 

 plexes, their precipitation by electrolytes. 



The theoretical discussion is followed by practical suggestions for carrying 

 out the agglutination test, and by a summary of results obtained in applying 

 the test to the investigation of the organisms which produce primary men- 

 ingitis in man. 



Experimental paratyphoid B fever. The mechanism of immunity in para- 

 typhoid B by ingestion. Vaccination by ingestion, A. Besredka (Compt. 

 Bend. Acad. Set. [Paris], 167 (1918), No. 5, pp. 212-214).— The author has 

 found it possible to produce human paratyphoid B in laboratory animals (rab- 

 bits) by ingestion of the organism after sensitization of the alimentary tract 

 with ox bile. The ingestion of heated cultures after sensitization with bile 

 renders the animal refractory to paratyphoid infection. This acquired im- 

 munity, as well as that possessed naturally by the animal, depends upon local 

 intestinal immunity. 



A filterable toxic product of the hemolytic streptococcus, A. H. Clark and 

 L. D. Fki.ton (Jour. Amcr. Med. Assoc, 11 (1918), Ko. IS. pp. 1048, 1049).—" It 

 has been found that hemolytic streptococci grown in rabbit's blood diluted with 

 Lock's solution yield a filtrate that is toxic for rabbits occasionally in doses as 

 low as 0.5 cc. per kilogram. The formation of this toxic material is dependent on 

 the presence of hemoglobin. It is destroyed by heating to 50° C. for 30 minutes, 

 it is dialyzable, it requires a certain incubation period in the animal before ex- 

 erting its toxic effects, it is nonhemolytic in vivo or in vitro, and it slowly loses 

 its toxicity on standing at ice-box temperature. An immunity can be rapidly 

 established against it, and the blood of immune rabbits when injected with the 

 toxin has the power of neutralizing its toxic effects. Rabbits immune against 

 the toxic substance are resistant to living streptococci." 



Antigangrenous serum therapy by a multivalent serum, H. Vincent and G. 

 Stodel (Compt. Raul. Acad. Set. [Paris], 167 (.1918), No. 6. pp. *45-247).—The 

 theory of the action of the multiple serum for gas gangrene previously noted 

 (E. S. R., 39, p. 885) is discussed, and the method employed by the authors in 

 the preparation of the serum is described. 



The method consists essentially of cultivating each pathogenic organism on 

 agar and then making a mixed emulsion in physiological salt solution. Flasks 

 containing the microbial suspensions are kept in the incubator at 3S° C. for 



