178 IMMUSITT. 



by means of a vacuum pump. This fluid is filtered through porce- 

 lain and evaporated in vacuo at from 20° to 36° to one-tenth its 

 volume or less. The concentrated enzyme solution is deprived of 

 inorganic salts and a part of its toxic constituents by dialysis, con- 

 tinued fix)m twelve to twenty-four hours. If after this treatment the 

 presence of toxic substances can be shown by animal experimenta- 

 tion, three-tenths per cent, of trikresol is added and the solution 

 allowed to stand for a few weeks longer, during which time appar- 

 ently the bacteriolytic enzyme destroys any trace of toxic substance 

 that may be present. The concentrated solution of enzyme thus ob- 

 tained has, according to Emmerich and Low, not only bactericidal 

 properties, but also the capability of destroying certain toxins, notably 

 that of diphtheria, in the animal body. As has been stated, these 

 authors were not able to immunize animals to anthrax with the 

 enzyme of the bacillus pyocyaneus, but this object they were able to 

 accomplish by the employment of their pyocyanase-immnneproteid. 

 This compound they have prepared in several ways, one of which is 

 as follows : To each 100 c.c. of the concentrated and dialyzed pyocy- 

 aneus culture, there is added from three to five grams of fresh, finely 

 divided spleen pulp. This mixture is treated with three per cent, 

 of potassium carbonate and digested at 37°. During this proc- 

 ess of digestion the suspended bits of spleen substance apparently 

 undergo a process of agglutination, resembling, on a magnified scale, 

 the phenomenon which may be seen in bacterial cultures. It has 

 been observed that the hay bacillus may develop in this mixture 

 daring the digestion process unless trikresol has been added. Fi- 

 nally the spleen pulp is apparently digested, while only small bits of 

 capsule and fiber remained undissolved. When this method is prop- 

 erly carried out there is formed, according to the statements of 

 Emmerich and Low, a nuclease-immuneproteid which will give com- 

 plete immunity against virulent anthrax, while the animal thus 

 treated shows no elevation of temperature, and seems to remain per- 

 fectly well in every respect. 



The nuclease-immuneproteid may be precipitated by the addition 

 of ten volumes of absolute alcohol, and when dried in vacuo over 

 sulphuric acid it may be kept for an indefinite time without loss of 

 bacteriolytic action. Pyocyanase-immuneproteid forms a homoge- 

 neous greenish or yellowish powder, which has been found to be ser- 

 viceable both in the production of immunity and in obtaining cure, 

 after it has been kept for two years. This substance is said to keep 

 better if about 5 per cent, of dextrin be dissolved in the bacteriolytic 

 solution before precipitation with alcohol. 



The importance of the claims of Emmerich and Low can hardly 

 be overestimated, provided they be confirmed by other careful work- 

 ers, and be found to be generally applicable to the infectious diseases. 

 To one who has followed the above given account of their investiga- 



