468 



SCIENCE 



[N. S. Vol. XXXI. No. 795 



The data derived from the continuous study, by 

 means of daily counts, of the organisms of a series 

 of hay infusions made by three standard methods 

 were summarized. The following general observa- 

 tions were made: 



1. The distribution of the organisms, broadly 

 speaking, is successively at the middle, top, mid- 

 dle and bottom of the infusion. The distribution 

 is determined primarily by the supply of food and 

 oxygen. 



2. The so-called cycle of organisms and their 

 distribution is not due to inherent changes in the 

 potentiality of division of the organisms, but to 

 progressive changes in the environment, i. e.. the 

 '■ cycle " is in the medium and not in protoplasmic 

 changes of the organism. 



3. Many species of infusoria do not resort to 

 conjugation to sustain rapid cell division when 

 the environment is slowly changing, but encyst 

 and remain at the bottom when the conditions 

 become somewhat unfavorable. Epidemics of con- 

 jugation usually occur when the environment is 

 rapidly changing. Data suggest that conjugation 

 may be a means of surviving acute changes in 

 the environment which, for example, preclude en- 

 cystment. 



The fauna and flora of the infusions were 

 studied by L. L. Woodruff and the chemical 

 changes by M. S. Fine. 



The Converse Relation between Ciliary and 'Neuro- 

 muscular Movements: Alfred 6. Mater, Car- 

 negie Institution of Washington. 

 Among the cations of sea water, sodium is the 

 most potent inhibitor of ciliary activity, and the 

 most powerful neuro-muscular stimulant. 



On the other hand, magnesium is the most 

 potent in maintaining ciliary movement, and the 

 most powerful inhibitor for neuro-muscular move- 

 ments. 



Potassium in weak concentrations, such as is 

 found in sea water, is a primary depressant for 

 cilia, but afterwards ciliary action recovers in its 

 presence. For neuro-muscular movements, how- 

 ever, it is at first a stimulant and finally a 

 depressant. 



Calcium is a weak stimulant for ciliary 

 movement, but a depressant for neuro-muscular 

 activity. 



A m monium at first stops and finally permits 

 of recovery of ciliary movement, but it at first 

 stimulates and afterwards inhibits neuromuscular 

 movements. 



Weak concentrations of acids (H ion) at first 

 depress and afterwards permit recovery of ciliary 

 movement, but they at first stimulate and after- 

 wards depress neuro-muscular movements. 



In each case the effect of the salt is exerted 

 through its cation. 



We may present these results in a graphic 

 manner if we represent a stimulus by a + sign, 

 and an inhibition of movement by a — sign, the 

 greater the effect the larger the print. Successive 

 effects may be represented by a succession of 



signs; thus: ■ 1- means a depression followed 



by recovery of movement and -| an initial 



stimulus followed by depression. Bearing this 

 preamble in mind, the following table will illus- 

 trate the effects of the various cations : 



Effect upon Effect upon 



Neuro-muscular Movement of Cilia 



Cations Movement of Animals 



Sodium _|_ 



^lagnesium _J_ 



Potassium -) • \- 



Caleium — -|- 



Ammonium -| f- 



Hydrogen -\ 1- 



Lithium + — 



Ringer's solutions, which consist of sodium, 

 potassium and calcium chlorides, are powerful 

 initial stimulants but finally produce depression 

 of movement and muscular tetanus. This dele- 

 terious effect can, however, be overcome by adding 

 magnesium, although this destroys the stimula- 

 ting influence of the solution. 



Sly experiments suggest that in surgical opera- 

 tions involving considerable loss of blood the 

 Kinger's solution, which it is the practise to in- 

 ject into the blood system to stimulate the heart, 

 should be followed after recovery from the shock 

 of the operation by a solution containing the 

 amounts and proportions of sodium, potassium, 

 calcium and magnesium found in the blood, thus 

 counteracting the injurious after-effects of the 

 Ringer's solution. 



The Summation of Stimuli in Invertebrates: 

 Frederic S. Lee, Columbia University, and Max 

 Morse, College of the City of New York. (In- 

 troduced by R. C. Osburn.) The paper will be 

 published in the American Journal of Physi- 

 ology. 



Summation of stimuli has been described in 

 both plants and animals and is a wide-spread 

 physiological phenomenon. It is usually ascribed 



