Apbil 8, 1910] 



SCIENCE 



553 



Our study of the body cells in the separator 

 slime has led to the following conclusions: 



1. Polymorphonuclear leucocytes of the neuro- 

 phile type, large mononuclear leucocytes, and 

 small lymphocytes appear normally in the sepa- 

 rator slime of the milk of healthy cows, and as 

 far as we can see they bear no relation to the 

 number of microorganisms present, including 

 streptococci. 



2. Eosinophiles may occur in the slime of the 

 separator. The cause and significance of their 

 presence remains problematical. 



3. The white corpuscles in milk of normal and 

 diseased cows, and in the blood of the same ani- 

 mals, ought to be studied, differentiated and 

 classified. Such a study will put the subject of 

 leucocytes in milk on a more exact scientific basis 

 than heretofore, and further our knowledge on the 

 significance of the relative number of the various 

 corpuscles in milk in normal and diseased condi- 

 tions of the cow in general, and in pathological 

 processes of the mammary glands and the udder 

 in particular. 



The details of our experiments and a critical 

 discussion of previous work will appear in the 

 January number of the Journal of Infectious 

 Diseases. 



A. Bacterial Disease of Alfalfa canned by Pseudo- 



monas medicaginis ( Saokett ) n. sp, : Waitee 



G. Sackett, Agricultural Experiment Station 



of Colorado. 



The disease has been known in Colorado since 

 1904, where, in some localities, it has caused the 

 loss of practically 80 per cent, of the first cutting. 



In the earliest stages, the stems have a yel- 

 lowish, olive-green color and appear watery and 

 semi-transparent; soon the color changes to an 

 amber, due to the appearance and subsequent 

 drying of a thick, clear exudate. This dried 

 excretion gives the stem a shiny, varnished ap- 

 pearance, and a slightly rough feel to the touch. 

 These stems blacken in six to eight weeks, become 

 very brittle and are easily broken, which fact 

 makes it almost impossible to handle the crop 

 without an immense amount of shattering. 



So far as our observations go, the disease is 

 confined principally to the stem and lower leaves; 

 it appears to run its course with the first cutting, 

 and those plants which have sufficient vitality 

 throw out a good growth for the second and third 

 cuttings. 



The disease has been shown to be due to a bac- 

 terium which lives in the soil, presumably, and 



this infected soil enters the plants through cracks 

 in the epidermis which are caused by freezing. 



Brief characterization: The causal organism is 

 a short rod with rounded ends, size 1.2 X .7 /j,, 

 actively motile by 1-4 bipolar flagella, non-spore- 

 forming and to which the writer has given the 

 name Pseudomonas medicaginis, n. sp. The organ- 

 ism forms filament but no capsules; Gram n^a- 

 tive. Surface pellicle in broth; shining grayish 

 white on agar, fluorescent green after three days; 

 gelatin colonies round, gelatin stab-surface growth 

 only, no liquefaction; potato discolored, moderate 

 growth, orange yellow, starch not destroyed; no 

 growth 37.5° C; no growth in Cohn's solution 

 growth in Uschinsky's solution. No liquefaction 

 rennet curd 40 days, no peptonization 25 days 

 no indol or hydrogen sulphide; nitrates not re 

 duced; ammonia from peptone and asparagin 

 fluorescent. Habitat — soil. Pathogenic for al- 

 falfa. Classification, Ps. 212.3332133. 



This paper, in full, is now in press as a bulletin 

 of the Colorado Agricultural Experiment Station. 

 A Comparative Test of Several Synthetic Media 



for the Isolation of B. coli: H. W. Ltall, 



Brown University. 



The three media studied were Harrison and 

 Vanderleck's esculin medium,' Dolt's asparagin 

 medium^ and Dolt's malic acid medium.' 



The total count, the number of red or black 

 colonies, and the per cent, of these which proved 

 to be B. coli were determined. 



The results are given in the following table: 



A = Pettaconsett intake — Pawtuxet River. 



B = East Providence intake — Ten Mile River. 



The conclusions drawn were that the esculin 

 medium is of about the same value as the stand- 

 ard litmus lactose agar over which it has no 

 advantages, the asparagin agar gives a much 



^ C. f. B., I., Orig. 51, 1909, 607. 

 'Jour. Inf. Dis., 5, 1908, 616. 

 'Ibid. 



