420 Erste Sektion: Cytologie und Protozoenkunde. Zweite Sitzung. 



larger numbers of cells are present than has been supposed. Re- 

 sults show that the average number of cells present in the milk 

 of normal cows is over i ooo ooo cells per cu. cm. and that as many 

 as 10 ooo ooo cells per cu. cm. may occur in milk sufficiently 

 normal in appearance to be sold as such by the highest class milk 

 dealers of Boston, Mass. There is great Variation in different cows 

 in respect to the number of cells present, the lowest count thus 

 far obtained for an individual cow being 50 000 while the highest 

 was 5 340 000 per cu. cm. 



The question whether these cells have any real sanitary 

 significance is dependent on their nature and on the causes which 

 produce the great variations in number which are known to occur. 



No very careful investigations to determine the origin of 

 these cells have been undertaken until recently. The cells bear 

 such a striking resemblance to the leucocytes found in the blood 

 and lymph that nearly all investigators have accepted this Inter- 

 pretation of their nature without question. Such an origin is 

 denied, however, by Winkler 1 ). He claims that the cells in 

 milk are detached epithelial cells derived from the lining of the 

 alveoli and discharged with the milk secretion. He claims that 

 the cells which have been regarded as leucocytes migrating 

 through the epithelium are in reality cells lying at the base of 

 the secreting epithelial cells which serve to regener ate it. The 

 discharge of the cells in the udder would then be analogous if 

 not homologous to the discharge of cells from the sebaceous 

 glands. If this origin be true then many of the assumptions which 

 have been made as to their sanitary significance fall to the ground. 



Moreover the claim that large numbers of these cells are 

 especially characteristic of abnormal conditions is supported by 

 insufficient evidence. The determinations already published have 

 been made by methods open to the criticisms noted above so that 

 it is fair to doubt the truth of any conclusion based on numerical 

 determinations alone. Not enough tests have been made by the 

 new method to assert confidently what the conditions are but 

 some things may be gathered from the following-examination of a 

 registered Holstein cow, age 3 years, in an early stage of lactation 

 (second milking) . The udder was inflamed and slightly indurated. 

 The average number of cells per cu. cm. was 1 53^ 000 for four 

 tests. This number is but little higher than the average number 

 number of cells for thirty seven apparently normal cows (ave. 

 — 1 125 000) in later stages of lactation. Seven of these cows ex- 

 ceeded the number given for the fresh cow mentioned above. 

 This particular cow has been mentioned because she might have 

 been expected to give an exceptionally high count for two reasons, 



J ) Zeitschr. f. landwirtsch. Versuchsw. in Österreich, n. Jahrg., p. 562 — 630, 

 Taf. I— IV, 1908. 



