386 
made when the plants were at the end of their vegetative period, while 
those of Frank were made shortly before their flowering, a fact that 
might have led to the difference in results. 
In Trifolium the tubercles are developed all the year round without 
being dependent upon the growth of the plant. It would appear that 
the biological process in these tubercles consists in the bacteria becom¬ 
ing transformed into bacteroids by a certain kind of hypertrophy, and 
that when dead the organisms are resolved into a fatty substance. 
The author is unable to believe in anything like a reabsorption of the 
bacteroids. The result of his examinations shows that the tubercles 
are not to be differentiated, either in their shape or in regard to their 
contents; thus no dimorphism is observable.—T heo. Holm. 
0 
Report on recent experiments in checking potato disease in the United 
Kingdom and abroad. London, 1892, pp. 193, figs. 5. 
Notwithstanding the fact that the potato is the standard crop, con¬ 
stituting the larger part of the food of the people of Ireland, and is 
an important product of England and Scotland; that the vegetable is 
known to have been affected by fungi since 1844; that the disease has 
in some years been so severe as to cause tremendous losses and even 
a famine in Ireland; and that for the past six years the disease has 
been known to be successfully combated by copper compounds, still the 
authorities of Great Britain do not seem to have made any attempt, 
to prevent the disease by treatment with these compounds until 1891. 
It is true that when the results of experiments made in France in 1838 
became known, the attention of the Government was called to them, 
but without any result, save the issuance of a report or two. In 1891 
the Boyal Agricultural Society of England began to make some experi¬ 
ments. The board of agriculture also began to bestir itself and to 
inquire of foreign consuls what progress had beeu made in checking 
the disease. The results of the experiments and inquiries are embodied 
in the report at present under notice, and which was issued by the 
board of agriculture in the spring of 1892. 
The report is divided into four parts: Part 1,contributed by Charles 
Whitehead, consists of a history of the disease; its cause; the life his¬ 
tory ot the fungus; and the action of “bouiliie bordelaise,” or Bor¬ 
deaux mixture, as it is commonly called. From this introduction it 
appears that although in 1840 Berkeley had shown the disease to be 
caused by a fungus, agriculturists generally up to as late a date as 1872 
believed the fungus to be the effect rather than the cause. This is shown 
by the fact that out of ninety-four essays submitted as the result of an 
offer of £100for the best account of the trouble and its remedies, not one 
was deemed worthy of the prize, and not one contained correct ideas as to 
its origin. This is certainly remarkable when we remember the number 
ot able botanists which England possesses and the demonstration by 
Berkeley twenty-five years before. The idea also at one time pre- 
