Converse Relation between Ciliary and N euro-Muscular Movements. 23 



dead flies, provided green algae, such as Spirogyra, be in the aquarium in 

 which it lives. It is very active, darting rapidly through the water. 



In 0.625 molecular sodium chloride it stops' instantly, but in weak 

 concentrations of sodium it may move for half an hour or more without 

 initial stimulation and with gradual loss of movement. 



In 0.375 niolecular magnesium sulphate it continues to move slowly 

 for about 90 minutes, gradually coming to rest. 



In solutions of about 0.066 molecular potassium chloride we some- 

 times observe that the initial effect is to check or stop all movement, 

 but after an interval of 2 or 3 minutes partial recovery takes place 

 and the spirillum moves slowly forward in a normal manner. A slightly 

 stronger concentration of potassium, however, checks movement with- 

 out permitting recovery. 



In 0.166 molecular calcium chloride it moves with normal activity 

 for from 15 to 30 minutes and then suddenly ceases to move. 



These reactions, it will be observed, are in each case identical in 

 nature with those of animal ciHa. In no other case, however, have I 

 been able to find a plant-spore which reacts as do the ciha of animals. 

 For example, another form of Spirillum living in this same dead-fly 

 culture in fresh water will continue to swim for somewhat more than 3 

 hours in 0.625 molecular sodium chloride, being even abnormally active 

 for the first few minutes in this solution. This spirillum is closely coiled 

 and exhibits irregularly-spaced nodes of milky or ground-glass-like trans- 

 lucency, contrasting with its general transparency (fig. 8 b). 



To cite another case, the actively motile zoospores of the Saprolegnia 

 which develops within the bodies of dead flies in fresh water will retain 

 some movement even after they have been in a 0.625 molecular sodium 

 chloride solution for 24 hours. In molecular magnesium sulphate they 

 remain motile for more than 9 hours, but are never so active as the 

 normal. In 0.625 molecular potassium chloride they are normally or 

 even supemormally active for 4 or 5 hours, but after this their move- 

 ments decline and die out after about 6 hours. In 0.166 molecular cal- 

 cium chloride they move normally for about 2 hours and then stop. 



The zygospores of Fucus illustrate another exceptional case. They 

 move slowly for from 13 to 19 minutes in 0.625 molecular sodium chlo- 

 ride, gradually coming to rest. In 0.625 molecular magnesium sulphate 

 they cease to move in from 4 to 8 minutes, and in solutions of potas- 

 sium chloride they soon cease to move, strong solutions stopping them 

 almost instantly. Altogether their reactions resemble those of the neuro- 

 muscular system of animals rather than animal cilia. 



I have thus met with nothing but confusion in attempting to corre- 

 late the reactions of plant spores with those of animal cilia, but it is still 

 possible that further study may demonstrate the existence of relation- 

 ships in the reactions of certain special forms of plants to those of animals, 

 but I doubt if any general significance can be attached to this even if it 

 be a fact. 



