l'^6- Journal of Applied Microscopy 



NORMAL AND PATHOLOGICAL HISTOLOGY. 



Joseph H. Pratt. 



Har\-ard University Medical School, Boston, Mass., to whom all books and 

 papers on these subjects should be sent for review. 



Vogel, K. Zur Histologie der Pneumonia The author studied light cases in which 



?79°r9oo!''°"''^' ^''^^'''' ^''"''°'' ^*' the fibrinous exudate of an acute lobar 



pneumonia was being replaced by con- 

 nective tissue. The origin and development of the new connective tissue was 

 investigated. 



Several staining methods were employed. Unna-Tanzer's orcein solution 

 followed by Loeft"er"s alkaline methylen blue yielded the best results. Orcein 

 colors elastic tissue brown. 



(1) Stain (3 to 24 hours in the following fluid : 



Orcein, ------ 0.5 



Absolute alcohol, - . - . . 40.0 



Distilled water, . - - . - 20.0 



Hydrochoric acid, ----- 0.5 



(2) Wash in water. 



(3) Decolorize about 30 minutes in — 



Hydrochloric acid, - - - . 5.0 



Alcohol ----.- 100.0 



Distilled water, ----- 20.0 



(4) Wash in water. 



(5) Stain 5 to 15 minutes in Loefier's alkaline methylen blue solution. 



(6) Decolorize for a few minutes in 70 per cent, alcohol. 



(7) Absolute alcohol. 



(8) Oil of origanum. 



(9) Canada balsam. 



In acute pneumonia fibrinous strands pass from the masses of fibrin in the 

 alveoli to the alveolar walls. Some strands enter Cohn's pores and unite with 

 fibrin plugs in other alveoli, others are attached to the wall. When resolution of 

 the exudate fails to occur the plugs of fibrin become retracted and clear spaces 

 are formed in the peripher}' of the alveoli. In early cases of organizing pneu- 

 monia, spindle shaped connective tissue cells are found on the surface and push- 

 ing their way into the interior of the fibrin plugs, and spindle cells are also seen 

 advancing along the threads of fibrin which pass through Cohn's pores. The 

 connective-tissue fibrillse form at first a loose network which contains in its 

 meshes many plasma cells. In one case new-formed elastic fibers were demon- 

 strable. 



Cohn thought that the connective-tissue arose from the inter-lobular and sub- 

 pleural tissues. Ribbert asserted that the formation began in the smallest bron- 

 chi and the bronchioles. Vogel opposes both these views. In the first stage of 

 organization he found young connective-tissue outgrowths springing from the 



