XIV Journal of Agricultural Research voi. iv 



Prickly-Pears as a Feed for Dairy Cows 



Page 



Plate F (colored). Opuntia cyanella, one of the principal species of prickly- 

 pear used in these experiments. Fig. I. — Mature joint. Fig. 2. — A flower 

 bud. Fig. 3. — Young joint showing rudimentary leaves. Fig. 4. — Flower. 

 Fig. 5.— A fruit 45° 



Plate LXI. Fig. i. — Singeing prickly-pear with a gasoline torch. Fig. 2. — 

 Cutting prickly-pear with a hoe, the blade of which is bent so as to be in 

 line with the handle 450 



Plate LXII. Fig. i. — Loading prickly-pear on a wagon. Fig. 2. — Type of 



cows used 450 



A Nasturtium Wilt Caused by Bacterium Solanacearum 



Plate LXIII. Bacterially wilted nasturtium plant from Baltimore, Md 458 



Plate LXIV. Nasturtium plants four days after inoculation by needle pricks 

 on the stem, using a pure culture of the bacteria cultivated from a plant 

 infected like that shown in Plate LXIII 458 



Plate LXV. Fig. i. — Nasturtium plant (tall variety) 13 days after inoculation 

 with Bacterium solanacearum from Creedmore (N. C.) tobacco, showing wilt 

 of the foliage and development of roots near needle pricks. Fig. 2. — Stem 

 of a nasturtium plant inoculated with Bacterium, solanacearum, from tobacco, 

 showing dark sunken stripe following line of infected bundle 458 



Plate LXVI. Fig. i. — Young tomato plants six days after inoculation by 

 needle pricks with the nasturtium organism, Bacterium solanacearum. Fig. 

 2. — Normal nasturtium stem enlarged to show uniform (unstriped) appear- 

 ance. Fig. 3. — A nasturtium stem inoculated with Bacterium solanacearum, 

 showing striping due to bacterial invasion of the bundles 458 



TEXT FIGURES 

 Wilt of Gipsy-Moth Caterpillars 



Fig. I. Drawingof polyhedral bodies as seen in smears of "wilted "caterpillars. 105 



2. Curve showing the mortality among 20 gipsy- moth caterpillars fed with. 



the wilt virus after filtration through the Berkefeld filter 118 



3. Curve showing the mortality among the 20 control gipsy-moth cater- 



pillars 119 



4. Cxirve showing the mortality among 20 gipsy-moth caterpillars fed with 



unfiltered wilt virus 120 



5. Curve showing the mortality among the 15 control gipsy- moth cater- 



pillars 120 



6. Curve showing the mortality among 15 control second-stage and third- 



stage gipsy-moth caterpillars 121 



7. Cm-ve showing the mortality among 26 control fourth-stage gipsy-moth 



caterpillars from Providence, R. I 121 



8. Curve showing the mortality among 8 control fourth-stage gipsy-moth 



caterpillars from Providence, R. 1 122 



9. Curve showing the mortality among 16 control fifth-stage gipsy-moth 



caterpillars 122 



10. Curve showing the mortality among 19 control fifth-stage gipsy-moth 



caterpillars 123 



11. Curve showing the mortality among 50 gipsy-moth caterpillars fed with 



wilt virus after filtration through the Berkefeld filter 123 



12. Cvu-ve showing the mortality among 25 gipsy-moth caterpillars fed with 



unfiltered wilt virus 124 



