September 8, 1922] 



SCIENCE 



285 



ing. And the experimental results apparently 

 contained considerable evidence that was not 

 deduced from them, concerning some of the 

 most fundamental questions of physiology. 

 For example, it is not very useful to know 

 rates of water or nitrate absorption from a 

 soil as the authors express these, but it would 

 be very enlightening to have these data ex- 

 pressed on the basis of the soil volume, or 

 simply as absolute weights. What I have in 

 mind, in this instance, is the question whether 

 the solvent water of the soil solution carries 

 the solute nitr-ate into the roots at its own rate 

 of capillary or imbibitional flow, or whether the 

 nitrate enters more or less rapidly than its 

 solvent. A little more logical analysis and 

 more attention to the deeper and somewhat hid- 

 den meanings implied in the experimental re- 

 sults might have strengthened the presenta- 

 tion very much. These suggestions are not 

 made here, however, as serious adverse criti- 

 cisms of the book I am reviewing. They are 

 introduced, rather, with the idea that they 

 may be a bit helpful in preparing the way for 

 studies that will carry our knowledge of root 

 ecology far beyond the present conceptions of 

 any of us. The experimental methods em- 

 ployed by the authors involve essentials that 

 are very promising indeed, and the results 

 here published form an excellent beginning 

 toward the illumination of one of the darkest 

 corners of physiological ecology. 



Burton E. Livingston 



SPECIAL ARTICLES 



SOME ALGAL STATISTICS GLEANED FROM 



THE GIZZARD SHAD 



In a recent paper^ the writer called attention 

 to the desirability of using the gizzard shad, 

 Dorosoma cepedianum Le Sueur, as collectors 

 of the plankton algje. These "living tow nets" 

 do not get caught on snags and roots, the 

 string does not break, and the algal collection 

 is very representative of the body of water 

 from which the fish were taken. It is necessary 

 only to oatch the young fish and examine their 

 stomachic and intestinal content to secure a 



1 The Ohio Journal of Science, 21, No. 4, p. 

 113, 1921. 



proportionate concentrated sample of the 

 plankton. In aquatic areas where the gizzard 

 shad are common these fish are well worth con- 

 sidering as aids in the collection of the plank- 

 ton algae. 



Through the courtesy of its director. Dr. 

 Stephen A. Forbes, the laboratory of the Illi- 

 nois State Natural History Survey sent me 

 some months ago several specimens of gizzard 

 shad, collected in certain streams and ponds 

 of Illinois during the late spring and summer 

 of 1899 and 1900. Rather extensive collections 

 of gizzard shad from Ohio, made during the 

 summers of 1920 and 1921, gave some inter- 

 esting statistics regarding the distribution and 

 abundance of the non-filamentous alga3 in 

 various localities of the state. A comparison 

 of the results of an examination of the stom- 

 achic and intestinal content of the fishes from 

 Ohio and Illinois reveals similarities and dif- 

 ferences in the algal fiora of ponds and streams 

 of the two states and in addition warrants some 

 conclusions concerning the algal food of the 

 gizzard shad in general. 



1. The total number of species and varieties 

 in an identifiable condition in the gizzard shad 

 from the two states is a hundred and fifty. 

 Very nearly identical forms indicate the phyto- 

 plankton similarity of the habitats from which 

 the fish were taken. 



2. The amount of mud present in the diges- 

 tive tract is in some cases considerably more 

 abundant in the Illinois fishes. It is not, how- 

 ever, in either case a matter of selection on the 

 part of the fish but rather a direct function of 

 the number of suspended mud particles present 

 in the water, i. e., it depends upon what enters 

 with the water as the fish swims along with its 

 mouth open. 



3. Diatoms are relatively much more abun- 

 dant in the Illinois fishes than in those taken 

 in Ohio. When a microscopic mount is made 

 of the intestinal content of some of the Illinois 

 specimens, little else except diatoms can be 

 seen. In this connection one might almost im- 

 prove upon the epitome of Dr. Mann:- "No 

 diatoms, no hake," for in that case it was 

 necessary to have herring and copepods as 



"- Ecology, 2, No. 2, p. 79, 1921. 



