634 



VITAL ACTIONS OF THE LOWER FUNGI. 



In fish and 

 Mrds. 



In man. 



attacked. Here, however, we can also recognise certain 

 predisposing factors ; thus it has been observed that 

 botrytis bassiana does not attack all silk-worms equally, 

 but chiefly young individuals, and more especially those 

 which are in a weak state as the result of imperfect 

 nourishment, &c. It is only by careful selection in the 

 culture of the silk-worms that this disease can be 

 combated. 



An infection by saprolegnia has been observed in 

 fish ; the fungus occasions, in the first place and very 

 gradually, a disturbance of the function of the skin, and 

 an affection of the gills, and, according to de Bary, the 

 disease develops only in fish which are already ill from 

 other causes. In the case of birds, mould fungi occur 

 comparatively frequently in the respiratory organs; 

 Bollinger* and Schiitz (see p. 124) have shown that 

 these fungi do not occur secondarily in organs pre- 

 viously diseased, but that they are the primary causes of 

 the disease ; they develop partly in the trachea and in 

 the bronchi, partly also in the tissue of the lungs and 

 in the cavities of the lung, and they cause severe dis- 

 turbance of the respiration, and ultimately lead to the 

 death of the animal. The forms which have as yet been 

 found are species of aspergillus and mucor ; possibly the 

 same which grow also in mammals and in man. 



In man epiphytic development of pathogenic mould 

 fungi is frequently met with on the external surface of 

 the skin, where they set up diseases of the skin (favus, 

 tinea tonsurans, &c.). Certain species of aspergillus 

 and mucor also frequently develop on collections of dead 

 portions of tissue, for example, on the coating of the 

 tongue, in the contents of a dilated stomach, in cavities 

 of the lungs, &c. ; also in the external auditory canal 

 and on the cornea, where they set up inflammation. If 

 spores of saprophytic mould fungi (penicillium) are in- 

 jected into the circulation of dogs or rabbits, they stick 

 on the walls of the capillaries, or in the endothelial 

 cells, especially in the liver, spleen, and medulla of bone, 

 and they may remain there for a long time without 



* Vortriifje im arzil. Vertin zu Miinchtn, 1881. 



