25^4 Journal of Applied Microscopy 



At the end of six hours the blood-vessels showed in places a loss of their 

 endothelium as well as a marked destruction of their elastic fibers. Groups of 

 bacilli lay in the lumina of the vessels, surrounded by polynuclear leucocytes. 

 After twenty-four hours epithelioid cells were found. The destruction of elastic 

 tissue was the more extensive the longer the duration of the infection. 



Wechsberg concludes that the tubercle bacillus destroys the fixed cells and 

 the intracellular tissue by its toxic action. It first injures the new formed cells 

 so that they are unable to produce connective tissue and blood-vessels. The 

 formation of giant cells indicates that the protoplasm of the proliferated cells 

 is only injured in part. Finally the new formed cells become entirely destroyed 

 and the stage of caseation is reached. j. h. p. 



H . . r TT 1 J- ^nT- 1 • J Recently an elaborate monograph on 



nerxheimer, G. Ueber die Wirkungsweise des •' . 



Tuberkelbacillus bei experimenteller Lun- the mode of action of the tubercle bacil- 

 gentuberkulose. Ziegler's Beitrage, 3i : 363 j^s has been written by one of Weigert's 

 -407, 1903. _ ■' ° 



assistants. It is in a sense a continua- 

 tion of the study begun by Wechsberg. Tubercle bacilli suspended in fluid 

 were injected into the trachea of rabbits and guinea pigs. The animals were 

 killed at different intervals, from one-half hour to seven weeks after the injection. 

 The staining method which gave the best results was a combination of Weigert's 

 elastic tissue stain and anilin-water-methyl-violet. The tubercle bacilli were 

 colored blue and stood out sharply upon the red background. 



1. Stain the sections in lithium carmine several minutes. 



2. Differentiate in 1 per cent, hydrochloric acid alcohol several hours. 



3. Stain in Weigert's elastic stain one hour. 



4. Wash rapidly in acid alcohol. 



5. Differentiate quickly in 96 per cent, alcohol. 



B. Stain in anilin methyl violet several hours in the cold. 



7. Differentiate in acid alcohol and in 96 per cent, alcohol. 



8. Dehydrate in absolute alcohol. 



9. Clear in xylol. 

 10. Mount in balsam. 



In order to remove the violet color from the celloidin the sections, after 

 treating with absolute alcohol, were dipped in an alcohol-ether mixture which 

 dissolves away the celloidin. 



The bacilli, as soon as they reached the lung, were taken up by the epithelial 

 cells lying free in the alveoli, and by cells still attached to the alveolar wall. 

 Desquamation of the epithelial cells soon followed the ingestion of the bacilli. 

 At the same time the bacilli exert a destructive influence upon the elastic fibres. 

 A result of the injurious action upon the cells and the intercellular substance is 

 a proliferation of the fixed elements ; a growth of epithelium occurs as well as 

 of endothelium and connective tissue cells. j. h. p. 



