HERBERT C. WARD 5 



jority of which showed tuberculous lesions from which the tubercle bacillus was culti- 

 vated. On the basis of these expermients Fontes concluded that the Much granules 

 represent a filter-passing stage of the tubercle bacillus. Spengler' noted, in tuberculous 

 sputum, granules somewhat like the Much granules in morphology but acid fast in 

 their staining reactions. In cultures from this material Spengler found the same acid 

 fast granules together with small acid fast bacilli. After some time the cultures re- 

 vealed acid fast bacilli of the normal size. These minute bacillary types Spengler 

 named "SpHtter" and regarded as filterable stages in the life of the tubercle bacillus. 

 Splitter forms were more frequently noted by Spengler in bovine lesions than in hu- 

 man, and this has subsequently been confirmed. 



A number of observers, such as Hauduroy and Vandremer^ and Valtis,^ have em- 

 ployed tuberculous discharges filtered free of adult tubercle bacilli and injected them 

 into animals. These animals later developed tuberculous lesions from which tubercle 

 bacilli were obtained. Valtis was unable to get cultures from his filtrates but found 

 multiple glandular enlargements in his inoculated guinea pigs. Many acid fast tuber- 

 cle bacilli were present in the visceral and pneumonic lesions. These animals reacted 

 to tuberculin just as did the animals inoculated with the unfiltered tuberculous ma- 

 terial. Valtis concluded that the filtrates from the tuberculous material contained the 

 tubercle bacillus in some exceedingly small form capable of passing his filters. His 

 conclusions have recently been confirmed by Arloingt who employed tuberculous 

 fluids from a variety of lesions and cultures of the tubercle bacillus. With carefully 

 controlled filters the filtrates were found to be sterile. In animals inoculated with the 

 filtrates the lymphatic glands were enlarged in a characteristic manner, and micro- 

 scopic examination revealed numerous tubercle bacilli. Finally, De Potter^ made use 

 of materials containing the avian type of the tubercle bacillus and controlled his fil- 

 trations with the minute organisms which cause chicken cholera. His filtrates were 

 sterile while his experimental animals developed tuberculous lesions from which the 

 avian tubercle bacillus was cultivated. 



Observations similar to those made on the tubercle bacillus have been reported 

 for a number of other organisms — for the dysentery bacillus by Hauduroy; for the 

 typhoid bacillus by Almquist, Fijgin, and Bergstrand; and for Bacillus coli by Izar 

 d'Herelle, and Tomaselli. The conception of filterable stages in these organisms does 

 not differ materially from that in regard to the tubercle bacillus, but the experimental 

 results are by no means as clear. For the present we can only state that very strong 

 evidence has been presented in favor of filterable stages in the tubercle bacillus, but 

 that more extensive confirmation of the work is necessary before the question can be 

 regarded as settled. 



SPECIAL ORGANS OF REPRODUCTION 



Intimately associated with the question of filterable stages is that of the presence 

 of special, complete morphological structures in the simpler bacteria analogous to the 

 ' Spengler, C: Ztschr.f. Hyg. u. Infektionskrankh., 49, 541. 1905. 

 ' Hauduroy, P., and Vandremer, A.: Compt. rend. Soc. de biol., 89, 1276. 1923. 

 J Valtis, J.: ibid., 90, 74. 1924; Ann. de I'lnst. Pasteur, 38, 453. 1924. 

 * Arloing, F.: Bidl. Acad, de med., Paris, 96, 301. 1926. 

 5de Potter, F.: Compt. rend. Soc. de biol., 96, 138. 1927. 



