Subcutaneous Malleiu Test. 709 



Preparation of Mallein. Mallein contains the toxic substance, endo- and exo- 

 toxin, of the glanders bacillus cultivated in a liquid glycerine medium. It was first 

 prepared by Helman and Kalning by extraction of potato cultures. Preusse as well 

 as Preisz prepared the material as follows: Potato cultures that have been permitted 

 to grow for several months are immersed in a mixture of equal parts of water and 

 glycerine and kept for several days in an incubator at 35° to 37° C. ; the liquid is 

 then steriliyed by means of steam and filtered through porcelain (in order to insure 

 greater uniformity of the product; Preisz adds bichloride of mercury). Eoux culti- 

 vates highly virulent glanders bacilli in glycerine-pepton-bouillon; at the end of 

 4 weeks the culture is sterilized, filtered and evaporated to i\ its original 

 volume (a similar method is recommended by Bang, also by Johne; the latter, 

 however, does not evaporate the filtrate, but adds nine volumes of a 2% solution of 

 carbolic acid). In Eussia, also, mallein is used in its dilute form in 1.0 cc. doses. 

 It is prepared by Kresling by cultivating a specially toxic strain of bacilli in 5% 

 glycerine bouillon for a period of 8 months. Foth evaporates the original bouillon 

 culture to ^^ i*^ volume, then treats the same with absolute alcohol, and in this 

 way obtains a white precipitate which subsequently becomes yellow; when dry this 

 leaves a spongy mass, which is readily pulverized (dry mallein). Schweinitz & 

 Kilborne produce a pulverized form of mallein by a similar method, while A. Babes 

 prepares his "Morvin," which is used almost exclusively in Roumania, by culti- 

 vating the bacilli on bouillon-potato medium ; 5-7 weeks later this mass is washed 

 on a Witt filter until the addition of alcohol to the filtrate no longer produces a 

 precipitate. Finally Schniirer attempted to produce an effective mallein by dis- 

 solving glanders bacilli in 2% antiformin solution, evaporating to Jg of its 

 A'olume aiid obtaining therefrom an alcohol precipitate. This preparation, though 

 it possessed properties similar to those of mallein, was only 1/15 of the strength 

 of Eoux's crude mallein. 



Crude mallein is a dark brown, syrupy fluid possessing a peculiar odor an<l 

 having a neutral or slightly acid reaction, if kept in a cool place and protected 

 from sunlight it retains its activity for months. When injected in large doses 

 (20 to 50 cc.) into the blood of healthy hor?es it may produce death, preceded by 

 Bymptoms of increased heart activity, respiratory difficulties and profuse sweat; the 

 subcutaneous injection of doses of 1.0 to 2.0 gm. into healthy horses produces no 

 morbid symptoms; on the other hand in horses affected with glanders even smaller 

 doses will produce a characteristic reaction. Experimentally infected guinea pigs 

 react both locally and generally to injections of 0.2 to 0.5 gm., while the injection 

 of 2.0 gm.' into healthy guinea pigs produces only temporary elevation of tempera- 

 ture (Pearson). 



The effectiveness of mallein varies according to the virulence of the strain of 

 bacilli used as well as to the method according to which it has been prepared. At 

 present we have no reliable methods of standardizing this material, aside from its 

 practical application in testing glandered horses. 



1. Subcutaneous Mallein Test (Thermic Reaction). Fol- 

 lowing the snbcntaneons injection of a suitable, comparatively 

 small dose of mallein glandered horses show a rise of body 

 temperature which usually begins in the fourth to eighth hour 

 after injection and rapidly increases for from 8 to 14 liours, in 

 exceptional cases not until the sixteenth or thirtieth hour, until 

 it reaches its maximum ; after this the temperature gradually 

 returns to the normal, but frequently a second less pronounced 

 elevation may be observed (Fig. 121). In the course of the 

 thermic reaction other fel)rile symptoms may also frequently 

 be observed (organic reaction) ; thus increased heart action 

 and respiration, which, however, are not always synchronous 

 with the change of temperature, muscular tremors, which, when 

 they occur at all, usually appear between the sixth and eighth 

 hour after injection; that is, in the beginning of the feljrile 

 attack; finally there may be depression, dullness and loss of 

 appetite, as well as a more or less extensive inflammatory 

 edematous swelling at point of injection (Fig. 122). (In the 



