96 Effect of Internal Influences. 



found in the secretion of one and the same part of the udder of a 

 cow at different times. 



In the same way it is impossible to establish rules for definite 

 differentiation of the streptococci of the yellow garget among them- 

 selves through the study of their morphological relations, by com- 

 parison of their biochemic characteristics or the pathogenic viru- 

 lence of individual strains, since the acid production and 

 acid susceptibility which are present in mastitis streptococci at first 

 may be easily changed by artificial means, and individual strains 

 have proven the possession of stronger, others a weaker pathogenic 

 action for test animals (Groning, Sven Wall). 



The author does not desire by any means to establish a theory 

 of unity for mastitis streptococci. To be sure there are marked 

 differences in the various strains, especially in regard to the pro- 

 duction of clinical symptoms, which cannot be attributed alone to 

 the variation of virulence, and to unequal resisting powers. 



It is possible that with the aid of newer methods of differ- 

 entiation (blood media, etc.) it will be possible to establish a fun- 

 damental type of mastitis streptococci in strains freshly cultivated 

 from animals. Even if with the continuance of cultivation new 

 characteristics, as for instance hemolytic properties, may be 

 acquired by the cultures, and the earlier characteristics become lost, 

 the characteristics acquired by the respective strains of streptococci 

 in their former growth may remain constant for a sufficient length 

 of time to permit the establishment of the type of varieties, as has 

 already been the case with the streptococci of man (Petruschky, 

 Schottmiiller, Baumann, Schulze and others). Enrst, Gminder and 

 others have demonstrated that the mastitis streptococci mostly 

 correspond to the mitior seu viridans or mucosus horn, group, 

 respectively. 



Based on the grounds previously described, milk hygienists, 

 bacteriologists, children specialists and veterinarians sometimes 

 more and at other times less imperatively have demanded the ex- 

 clusion of cows with streptococcic mastitis from the production of 

 milk (Jensen, Weigmann, Blevel, Sven Wall, Ruhm, Trommsdorff, 

 Seiffert, Ernst and others). 



This requirement is natural from the hygienic standpoint, but 

 its practical execution is rendered very difficult by the remarkable 

 prevalence of the disease, and as a matter of fact as long as the 

 general control of production and the examination of milk of indivi- 

 dual cows are not required a thorough enforcement cannot be 

 hoped for. 



For the present the exclusion from the market of all milk which 

 shows changes in a recognizable way, as for instance through a 

 collection of yellow sediment, should be considered satisfactory. At 

 the same time from an economic standpoint only milk from affected 

 quarters should be excluded, while the sale of milk from healthy 

 quarters should be allowed. 



