202 AGRICULTURAL REPORT. 



Acatlciuy of Scieuccs, statetl tliat the starch of fuugoid potatoes is uot 

 injured, "aii<l during- the present year Dr. Hooker, of Kew Gardens, 

 jjondon, has, after a microscopic examination, made a public statement 

 to the same effect. 



Starch manufacturers, on the other hand, have stated in the columns of 

 the English scientiiic monthlies that, while they do not deny the state- 

 ments of these scientists, they affirm that a large portion of the starch 

 of the rotting potatoes will not sink and is washed away. The results 

 of my investigations, as above described, will, I think, sufficiently ex- 

 plain the discrepancy between the savaus and the manufacturers. To 

 subject the matter to a practical test I placed a portion of the rotting 

 potato in a muller and ground it into a very fine pulp, thereby ruptur- 

 ing the third ceil. I next placed the pulp in water. After twenty-four 

 hours I examined, microscopically, the precipitate and the whitish mat- 

 ter floating in the column of water. I found the whitish substance to 

 be cellulose, or broken cells, while the precipitate was pure starch, show- 

 ing that the starch had escaped from the cells by the extra friction. Mr. 

 Martin McKinzie, of Boston, Massachusetts, wrote to the Department 

 under date November 1, 1872, stating that, in a field near his residence, 

 Early Eose and Jackson White potatoes were planted last season, adjoin- 

 ing each other; the first, or Early Rose, proved nearly an entire failure 

 from blight-fungus ; while the second, or Jackson Whites, grew to per- 

 fection. Not the slightest appearance of blight was manifested in any 

 instance on them. The writer further states that the conditions of plant- 

 ing, manuring, and soil, were practically the same in each case. Facts 

 similar to these have been collected from time to time, and form an impor- 

 tant point for further observation. They indicate a strong probability 

 that the disease may be due to the condition of the ])Otatoes used as seed. 

 It has been frequently stated "that the potato, from high cultivation, 

 has run out, and that recourse should be had to the seed of the plant as 

 a means of renewing the crop." The terms "high cultivation," if they 

 have any practical meaning, must signify that an internal organic struct- 

 nral change has taken place. It may be that the vascular bundles, or 

 air-cells, occupy a larger relative space in the highly-cultivated potato, 

 so called, than they did when this vegetable first became an object of 

 public interest ; if so, this alone might in part explain one of the great 

 causes of potato-rot. The fact that the disease in the potato always 

 appears first in the vicinity of the air-cells, would seem to fortify this 

 idea, and investigation in this line might iirove i)rofitable. 



A superabundance of moisture and heat produces rank vegetable 

 growth. The first structure formed consists of cellulose cells, which 

 may include the vascular bundles and other forms of cellular tissue. 

 Nitrogenous cells next follov/ as a lining to cellulose cells, and within 

 these again form cellulose cells, which, in the case of the potato, contain 

 the starch, and the more likely is this the mode of action from the fact 

 that starch may be made from the nitrogenous matter, while 'the latter 

 cannot be made from the former. It is evident that the Jackson Whites, 

 in the case alluded to, were proof against the attacks of fungi, although 

 surrounded by them, and the inference might be drawn that the seed of 

 the Jackson Whites was in a more favorable condition when planted 

 than was that of the Early Eose, and hence the assimilations of the 

 plants were not retarded. The savans of Europe, according to the 

 English monthlies, have nothing better to offer as a remedy than the 

 cutting olT the stalks the moment the brown blotches appear. This may 

 be the" best mode of preserving the tubers as an article of food, under 

 the circumstances ; but in the absence of stalks, leaves, and the healthy 



