156 



Aquatic litt 



fish-eating birds and in guano. Dr. Car- 

 penter considers that the diatoms are an 

 important factor in maintaining the equi- 

 librium of life in the South Polar Ocean, 

 "since there is a marked deficiency in 

 this region of the higher forms of vege- 

 tation, were it not for them there would 

 be neither food for aquatic animals, nor 

 (if it were possible for these to maintain 

 themselves by preying on one another) 

 could the ocean be purified of the car- 

 bonic acid which animal respiration and 

 decomposition would be continually im- 

 parting to it." 





: 



Heliopelta 



Arachnoidiscus 



Drawnings by Author 



The diatoms play a not inconsiderable 

 part in the economy of mankind as they 

 form a component part of metal polishes 

 that are abrasive in action. Quite a num- 

 ber of much-used tooth and metal pol- 

 ishes contain them. I have a slide of 

 freshwater forms taken from "Silver 

 Suds" polishing powder, which was pre- 

 pared by Mr. Frank J. Keeley. The well- 

 known "turkey-stone." so much used for 

 sharpening edged tools, is composed of 

 the remains of diatoms. Throughout the 

 world there are numerous almost pure 

 fossil deposits, often of considerable ex- 

 tent. Richmond, Virginia, is underlaid 

 by a stratum of diatoms, in some places 

 lying fifty feet below the surface. Such 

 deposits were formed while the locality 

 was under water, and similar ones are 

 being formed today. It is from such 

 fossil formations that the material is 

 taken for commercial purposes, provided 



it be pure and not contain other matter 

 difficult to separate. 



The fresh-water species may be col- 

 lected in springs and roadside ditches, 

 appearing as dark amber patches. Almost 

 pure collections can be made with a 

 pipette, and may be seen to glisten in the 

 sunlight. They will grow almost indefi- 

 nitely in small vessels, which may be 

 termed "micro-aquaria," and will be a 

 continual source of delight to those hav- 

 ing a microscope with which to study 

 them. 



In all scientific research, while special- 

 ization in some one line is to be encour- 

 aged, and is indeed necessary, in order 

 to reach a point where one's work is of 

 real value, yet we should build on a 

 broad foundation, by acquiring a good 

 general knowledge of scientific subjects, 

 for by so doing we are better able to 

 wrestle with the problems we are sure 

 to meet. — E. E. Hadlcy in Lorquinia. 



None but the well-bred man knows 

 how to confess a fault, or acknowledge 

 himself in error. 



"Why does the Professor have all 

 those letters tacked on to his name?" 



"That shows he got there by degrees." 

 — Exchange. 



Aquatic Life has proven very attrac- 

 tive and helpful. It would seem almost 

 a sacrilege to criticise it.— Aerich Bur- 

 meister, Manager, Pacific Goldfish 

 Company. 



I am inclosing one dollar for renewal 

 of my subscription to Aquatic Life. 

 In your last number I found an article 

 that was worth more to me than the cost 

 of the year's subscription. — John C. 

 White, Alabama. 





