ANALYSIS OF ORGANISMS 177 



McHargue made quantitative determinations of the various kinds of 

 nitrogen in the grasshopper and June bug material along with those in 

 beef roast and breast of turkey; he found that the different kinds of 

 nitrogen in these two insects were similar in amount to those noted for 

 the beef and the white meat of turkey. 



In the samples shown in table 49 the crude protein, the ether extract, 

 the crude fiber, and the ash make up from 34.13 per cent in Spirogyra 

 to 95.42 per cent of the dry weight of the material in Cyclops ; in other 

 words the nitrogen free extract ranges from a minimum of 4.58 per 

 cent in Cyclops to a maximum of 65.88 per cent in Spirogyra. On an 

 ash free basis from 4.89 per cent to 72.46 per cent of the organic matter 

 in the various samples consisted of nitrogen free extract. 



The samples of plant material, in general, contained a larger per- 

 centage of nitrogen free extract than the animal samples. In the 

 former the largest percentages were found in the non-plankton forms, 

 that is, in Spirogyra, Cladophora, Potamogeton, Vallisneria, and Myrio- 

 phyllum. With the ash included the smallest percentage of nitrogen 

 free extract is recorded for the diatom sample, but on an ash free basis 

 it is a sample containing Aphanizomenon and Anabaena. In the non- 

 plankton plant material from 47.85 per cent to 72.46 per cent of the 

 organic matter consisted of the undetermined carbohydrates which 

 made up the nitrogen free extract, while in the plankton algae these 

 carbohydrates constituted from 27.62 per cent to 54.82 per cent of the 

 organic matter. 



In the thirty-three samples composed of animal material the sum of 

 the percentages of crude protein, ether extract, crude fiber, and ash is 

 smallest in Chironomus tentans (65.0 per cent) and largest in Cyclops 

 (95.42 per cent), making the range of the nitrogen free extract in these 

 samples from 4.58 per cent in Cyclops to 35.0 per cent in Chironomus 

 tentans. With the exception of Chironomus tentans and one of the 

 Daphnia samples, the nitrogen free extract constituted less than 25.0 

 per cent of the dry weight of the material in the animal samples. 



No attempt has been made to ascertain the composition of the nitro- 

 gen free extract in these samples of animal material, but the greater 

 part undoubtedly consists of carbohydrates. Some fatty compounds 

 are not entirely extracted with ether, so that, in some instances, small 

 amounts of fats may be included in the nitrogen free extract, and pos- 

 sibly other substances are present also. The nitrogen free extract 

 amounts to more than 10.0 per cent of the dry material in twenty-four 

 of these animal samples and to more than 20.0 per cent in eight of them ; 

 if this extract is regarded as chiefly carbohydrate in character, it means 

 that these samples contain fairly large percentages of carbohydrates, 

 especially the latter group. In various analyses carbohydrates are not 



