184 EXPERIMENT STATION RECORD. 



The examinations of the quantities of dirt in the milk showed that 

 35 samples out of a hundred contained less than 0.5 mg. per liter, and 

 the average amount for 65 samples was 2.44 mg. The maximum con- 

 tent obtained was 10.6 mg. This favorable result is explained by the 

 fact that on most Finnish dairy farms strict attention is paid to clean- 

 liness in the stables and grooming the cows. The samples of milk 

 examined were found to contain a very low percentage of fat; in the 

 case of 100 samples only 68 came above 2.7 per cent. This is due to 

 skimming or admixture of skim milk. — f. w. woll. 



The invasion of the udder by bacteria, A. R. Ward [Neio York 

 Cornell Sta. Bui. 178, pp. 260-280, pi. l^figs. 2, dgm. 7).— The views 

 of several investigators regarding the presence or absence of bacteria 

 in the normal udder are noted, and investigations conducted by the 

 author in continuation of earlier work (E. S. R., 10, p. 1094) are 

 reported. 



Bacteriological examination was made of the udders of 19 cows, 

 slaughtered on account of tuberculosis. None of the udders examined 

 showed tubercular or other lesions. Plate cultures were made from 

 the fore milk drawMi just before the cows were killed and from gland- 

 ular tissue of different portions of the udder, great care being taken 

 to prevent contamination. Bacteria, for the most part micrococci, 

 wTre found in nearly all cases, and summaries are given of the mor- 

 phology, staining reactions, and cultural characteristics of the several 

 kinds. The same kinds of bacteria were frequently found in the fore 

 milk and in the glandular tissue. The germs isolated from the udders 

 did not usually cause the souring of milk in cultures. Tables and dia- 

 grams show the sources of the different germs and. their distribution 

 in a number of the udders examined. 



A study of the structure of the udder revealed no obstruction sepa- 

 rating the milk cistern from that of the teat sufficient to prevent the 

 invasion of bacteria. 



"The free communication of the milk cistern with the more minute lactiferous 

 ducts is at times interrupted by the sphincter muscles described by anatomists as 

 present in those ducts. There is little ground, however, for considering them as 

 serious barriers to the progress of micro-organisms 25000 of an inch in diameter. 



"That the milk ducts of the teat normally harbor bacteria is admitted l>y ail. 

 Some few, with whom the writer agrees, assert that the milk cistern normally har- 

 bors bacteria. Such being true, there is little reason to doulit that bacteria may find 

 their way through the fine ramifications of the milk cistern (lactiferous ducts) to 

 regions remote from the teat. Pathogenic organisms certainly do so when the udder 

 is diseased, and to couceive that harmless ones do so in health is not difficult." 



The author briefly discusses the practical bearing of the results of 

 the investigation. 



"Judged from the standpoint of the dairyman, who considers that souring is the 

 one and only harmful change in milk, the contamination of milk from the interior 

 of the udder, so far as has been shown in this work, might be disregarded as unim- 

 portant. Until more is known of the ordinary and of the occasional bacterial 



