*92o] SEIFRIZ— PROTOPLASM 369 



pea Lathyrus maritimus, and of the dog's-tooth violet Erythronium 

 revolutum; the protozoa Amoeba and Euplotes; the sand-dollar 

 Echinarachnius; and the sea-urchin Tripneustes esculentus. 



* 



The experimental work on these forms was done mostly in the 

 Botanical Laboratory of the Johns Hopkins University. The 

 work on Fucus, Echinarachnius, and part of that on Myxomycetes 

 and pollen tubes was carried on at the Harpswell* Laboratory, 

 South Harpswell, Maine. 7 The work on Tripneustes was done at 

 Ocho Rios, Jamaica, B.W.I. 8 



I am greatly indebted to Professor Duncan S. Johnson for 

 first pointing out to me the possibilities of microdissection as 

 applied to the study of living protoplasm, and for assistance during 

 the progress of this work. To Professor Robert Chambers of 

 the Cornell Medical College, New York City, my thanks are due 

 for many suggestions relative to microdissection. I wish also to 

 acknowledge the help received from Dr. Charles V. Taylor per- 

 taining to the structure and behavior of the protozoan Euplotes, 

 and from Dr. Howard E. Pulling, then of this university, pertain- 

 ing to problems in physical chemistry. To Professor Warren K. 

 Lewis of the Medical School of this university I am indebted for 

 the loan of the microdissection instrument used in this work. 



\ 



Myxomycetes 



The consistency of Myxomycete protoplasm when in the active 

 vegetative state is liquid (v.v. 3). One is quite likely to be misled 

 by the apparent ease with which a needle traverses protoplasm 

 into believing that the protoplasm is of watery consistency. Super- 

 ficial observation of streaming protoplasm also leads one to believe 

 that it must be very liquid, while, as a matter of fact, it may be 

 rather viscous, as in bread mold. A good indicator of the degree 

 of viscosity, when the protoplasm is of low consistency, is the 

 distance from the path of a moving needle at which granules are 

 disturbed. The presence of Brownian movement suggests a low 

 consistency. 



7 1 am indebted to Director J. S. Kixgsley lor the use of a room at the Harpswell 

 Laboratory. 



8 To Frank ClTNDAIX I am greatly obliged for his kindnes- in placing the facilities 

 of the Institute of Jamaica at my disposal. 



