86 MIDLAND NATURALIST 
cesses will repay for many failures. At the very outset we shall 
find that growing algae in the laboratory will be, on the whole, 
an easy matter in spite of the fact that at present we know very 
little about the subtle influences to which these plants respond. 
We may often feel obliged to refer our successes to luck, but as the 
chances of success and failure are about equal on the average, the 
results of the game are worth the venture, and after a number of 
failures we come to feel that a series of successes are due to us as 
a result of effort, while he that never tries dares not even hope to 
succeed even onc 
Nearly all "o plants ordinarily demanded by the common text 
as types for instruction can, with reasonable foresight be obtained 
in the laboratory aquarium by development, or be found out of 
doors in nearby ditches and pools. Often preserved material 
answers our demands almost as well as live material, so that if any 
particularly good specimens are found in the field, they should be 
gathered and ‘‘pickled’’ in as large a quantity as obtainable. 
Though plants will often appear annually or periodically in places 
where once found, it is well to consider that the next periodical 
appearance in abundance in any given locality may be as long as 
ten years away, and that it is therefore best to obtain as much 
as possible even at the cost of considerable inconvenience. 
We know little or nothing about the periodicity of the reap- 
pearance of algae in any given place, and hence there is no other - 
circumstance when it is so-much worth while to make the best of 
an opportunity, as in case of an abundant appearance of some rare 
specimen of algae. 
I shall first discuss some general considerations helpful to suc- 
cess in growing algae in the laboratory, oed then give detailed 
methods for some common individual specimen 
The first and most common mistake nde by those that 
attempt to keep algae alive in the laboratory is to change the water 
in which these plants are. The motive for so doing is a well in- 
tended one, but there is a fallacy connected with it. 'The reason 
usually given is that a change of water prevents decay by the 
action of bacteria. Paradoxical as it may seem there are few if 
any of the hardiest algae that can stand such hard treatment 
though well meant. 
A little reflection will show that since it is so difficult for the 
lower plants to accomodate themselves to their environment, a 
