Apr. i-sept. IS. 1921 Illustrations ix 



Page 

 dium from maize germinating in dew on the leaf surface. L. — Conidium 

 from maize giving rise to extensive branching hyphae in a dilute decoc- 

 tion of young maize kernels 122 



Effect of Drugs on Milk and Fat Production 

 Text Figures 



1. Graph showing effect of tonic mixture No. i on butter-fat and milk yield. . 127 



2. Graph showing effect of air-slaked lime on butter-fat and milk yield 127 



3. Graph showing effect of Fowler's solution of arsenic on butter-fat and milk 



yield 128 



4. Graph showing effect of powdered gentian on butter-fat and milk yield 128 



5. Graph showing effect of the German tonic mixture on butter-fat and milk 



yield 129 



6. Graph showing effect of physostigmine sulphate on butter-fat and milk yield 129 



7. Graph showing effect of sodium bicarbonate on butter-fat and milk yield. 130 



8. Graph showing effect of ginger on butter-fat and milk yield 130 



Halo-Bught of Oats 

 Plates 



C. Halo lesions on flag leaves of Wisconsin No. 14 oats 172 



26. Typical isolated halo lesions 173 



27. Halo lesions on Wisconsin No. 14 oats produced by spraying with a water 



suspension of the stock organism May 26, 1917 172 



28. Infection from imtreated 1916 seed of Wisconsin No. 124 oats 172 



29. Spikelets of Wisconsin No. 14 oats: A. — Left and center spikelets show 



natural infection with halo-blight. B. — Upper spikelet shows typical 

 isolated halo lesion near base 172 



30. A. — Two per cent -I-5 glucose Difco peptone-beef bouillon agar slant of No. 



36. B. — Two per cent potato-dextrose agar slants 172 



3 1 . A. — ^Three-day colony of stock on 2 per cent dextrose-potato agar. B . — Two- 



day colonies of stock on -fio beef-peptone agar. C. — Five-day colony of 

 stock on potato-dextrose agar. D. — Five-day colony of No. 36 on -fio 

 beef -peptone agar. E.— Three-day colony on 2 per cent glucose Difco 

 peptone beef bouillon agar. F. — Seven-day colony of stock on -f 15 beef- 

 peptone agar. G. — Margin of 3-day colony of stock on -\-i^ gelatin 172 



32. A. — Five-day colonies of stock on potato-dextrose agar. B. — ^Three-day 



colony of stock on potato-dextrose agar 172 



33. Isolations from sections of halo lesion 172 



34. A. — No. 36 from 24-hour potato-dextrose agar slant; carbol fuchsin stain. 



B. Stock from 2 4-hom- potato-dextrose agar; Ribbert's capsule stain. C. — 

 Stock from 4-day potato-dextrose agar; carbol fuchsin stain, showing 

 long chains. D. — Stock from 3 -day potato-dextrose agar; Ribbert 's cap- 

 sule stain. E. — Stock from i-day -f 15 beef-peptone agar; Van Ermengem 

 stain. F.^No. 36 from i-day -I-5 beef-peptone agar; Caesar-Gil stain. . 172 



35. Sections of oat leaves through halo lesions, showing bacteria in the tissues. 172 



Behavior of the Citrus-Canker Organism in the Sou, 

 Plates 



36. A. — Citrus-cankers on mature wood of trunk of Citrus aurantifolia. B. — 



Citnxs-cankers on mature wood of branches of Citrus aurantifolia 206 



418°— 21 2 



