1900] CHANGE OF FORM IN GREEN ALG& 309 
stimulus to which the alga responds by a change of form is a 
change in the osmotic pressure of the surrounding fluid. This 
must be accompanied by a corresponding change in the relation 
of water to the protoplasm. Whether or not extraction of water 
brought about by solutions of non-electrolytes or by evaporation 
from a moist substratum will be accompanied by the same 
response as that brought about by a solution of electrolytes, my 
experimentation has not yet gone far enough to show. It is 
worthy of remark, however, that when found wild this alga was 
in the palmella form, and was growing in air on moist bark. 
Loeb® has recently brought about artificial parthenogenesis, both 
in the eggs of echinoderms and annelids by placing them in a 
solution which would extract water from them osmotically. The 
fesult was the same whether electrolytes or non-electrolytes 
Were used. Thus in these eggs the phenomena of segmentation 
and growth are profoundly influenced by osmotic pressure. 
Whether or not his results have any connection with those given 
in the present paper is an open question. The recent work upon 
Various Stains and forage plants by Buffum and Slosson? fur- 
hishes data which may have a somewhat closer connection with 
Nyown. Absorption by seeds, their germination, and the growth 
of the plant were all greatly retarded in a strong solution and 
*celerated ina weak one. And this was true without regard to 
: €chemical nature of the dissolved substance ; a number of 
-Clectrolytes were used and also non-electrolytes. On the other 
of Sal €xperiments have not been at all in accord with those 
Peland (doc, cit.) when he found, with peas, maize, and 
F 
atten J.: Further experiments on artificial parthenogenesis and the nature of 
as fertilization, Amer. Jour. Physiol. 4: 178. 1900. 
170. 1900, * Attificial parthenogenesis in annelids (Chztopterus). Science N.S. 12: 
9 . = 
hie “) SLosson, E. E., and Burrum, B. C.: Alkali studies I, Bulletin 39 Wyo 
: ( Exp. Sta, 189 : 
2 * ‘ 
Bap uteM B. Cu: Alkali studies III, Ninth Ann. Report, Wyoming Agri. 
XP. Sta, 1899, . 
(3) SLosson, 
a) By E.E.: Alkali studies IV, same. 1899. 
ee and SLosson, E. E.: Alkali studies V, Tenth Ann. 
Report, 
Joming Agric, Exp. Sta. 1900 
