posed that this substance be called "asearase." His investiga- 

 tions showed that asearase was readily diffusible and that it 

 either is or is associated with a substance of the order of a 

 primary albumose. It was precipitated by ammonium sulphate 

 and 70 per cent alcohol, and was not destroyed by trypsin. 

 Asearase did not inhibit the action of papain. Von Bonsdorff 

 (1939) was unable to confirm the existence of antitrypsin or 

 antipepsin in Ascaris extracts, but he did find that the extracts 

 inhibited proteolysis of casein bv depepsinized gastric juiee at 

 pH 7.4. 



Stewart and Shearer (1933) studied the digestion of pro- 

 tein by infected and noninfected sheep and concluded that the 

 nematodes of the stomach inhibited the normal digestive proc- 

 esses. They then obtained an extract from the worms which 

 was capable of producing a 40 to 7') per cent inhibition of the 

 peptic digestion of casein. For this sulistance and for similar 

 antienzymes of nematodes they siiggested the term ' ' nezyme. ' ' 

 Andrews (1938) could not repeat the results of Stewart and 

 Shearer on the lowered digestive action of infected sheep. He 

 found that the digestibility coefficients were the same in infected 

 and noninfected animals. Infected sheep did not gain weight 

 as rapidly as controls, but Andrews concluded that this was 

 probably caused by intestinal irritation. 



The existence of antienzymes has also been reported for 

 cestodes. However, de Waele (1933), on the basis of experi- 

 ments on Taenia sagiiiata, has questioned the existence of anti- 

 enzymes and has assumed that protection of the worms from 

 enzyme action is due entirely to the resistance of the cuticle. 

 One basis for this assumption is found in the fact that pieces 

 of worms but not whole worms may be digested by trypsin. 

 This conclusion is sub.iect to criticism in that when worm frag- 

 ments are placed in an enzyme solution considerable dilution 

 of any antienzyme may occur by diffusion and the antienzyme 

 may thereby be rendered ineffective. In view of the chemical 

 isolation of the antienzyme mentioned above (Hamill, 1906; 

 Nash and Harned. 1932; Collier, 1941) de Waele's conclusion 

 certainly can not Ije extended to the nematodes. 



General Chemical Composition 



DRY WEIGHT 

 There have been only a few determinations of the dry weight 

 of parasitic nematodes, and the values recorded are fairly high. 

 The average figures reported for Ascaris lumbricoidcs are 20.7 

 percent (Weinland, 1901) and 15 percent (Flury, 1912), for 

 Parascaris, 21 percent (Schimmelpfennig, 1903) and 14.8 per- 

 cent (Flury, 1912), and for a larval EiistrongtiUdes, 25 percent 

 (V. Brand", 1938). Flury (1912) measured the dry weight of 

 various parts of the body and obtained the following results: 



Dry weight in percent of fresh weight 

 Ascaris fnmbricoidrs Parascaris equorum 



Body wall ..- 23.5-25.0 25.0 



Alimentary tract 27.5 24.9 



Body fluid - 4.0- 6.7 5.0 



Reproductive organs ... 25.0-33.3 24.0-27.4 



It can be calculated from Flury 's figures that these values 

 represent the following fractions of the total dry weight: body 

 wall 65 percent, alimentary tract 3 percent, body fluid 10 per- 

 cent, and reproductive organs 20 per cent. 



CARBOHYDRATE.S 



Storage of carbohydrates in the form of polysaccharides 

 seems to be quite common among the parasitic nematodes. .W- 

 though chemical analyses have been made only for Ascaris, it 

 seems likely that in this respect other species are very similar. 

 Weinland (1901) and Flury (1912) found an optical rotation 

 of +183° to +193° for the polysaccharide of Ascaris. Since 

 these workers and Campbell (1936) identified the sugar result- 

 ing from hydrolysis as glucose, and since the solubility of the 

 polysaccharide and its color reaction with iodine are typical 

 of glycogen, it seems probable that the substance is true glyco- 

 gen. Campbell (1936), however, observed antigenic properties of 

 a polysaccharide fraction isolated from Ascaris. It does not seem 

 likely that pure glycogen would be capable of inducing the for- 

 mation of specific anti-bodies. One should therefore expect that 

 another polysaccharide is associated, perhaps in very small 

 amounts only, with the glycogen. However, in so far as meta- 

 bolic processes are concerned, it is justifiable to speak of 

 glycogen alone. 



The occurrence of large amounts of glj'cogen in ascarids was 

 established in a qualitative or semi-quantitative wav by Claude 

 Bernard (1859) and Foster (1865), but Weinland "(1901) was 

 the first to undertake a large series of quantitative determina 

 tions. The more recent data on the glycogen content are sum 

 marized in the following table: 



Apparently the glycogen content of parasitic nematodes is 

 always high. The lowest value amongst the intestinal nema- 

 todes was found in Ancylostoma. This may be related to the 

 fact that the hookworms have access to larger amounts of 

 oxygen than the other intestinal helminths. It is curious that 

 A.scaris lumbricoidcs analyzed in Denmark and Russia yielded 

 higher average glycogen values than those in USA and Ger 

 many. It is unknown whether this is caused by a different 

 diet of the host and therefore of the parasite in various couu 

 tries, or merely to different handling of the pigs before slaugh- 

 tering. 



Sexual differences in glycogen content of parasitic nematodes 

 do not seem to be pronounced. Smorodincev and Bebesin (1936) 

 and Toryu (1933) found more glycogen in females than in 

 males of Ascaris and Parascaris. Von Brand (1937), on the 

 other hand, found slightlj' more polysaccharide in male as 

 carids. 



So far, only adult nematodes of warm-blooded hosts have 

 been analyzed, and contrary to what is known about many 

 free-living invertebrates, no evidence of seasonal variation in 

 the amount of stored glycogen has been found. The obvious 

 explanation of this difl'erence lies in the uniform conditions 

 under which the parasitic organisms live throughout the year. 

 From this viewpoint, it should prove interesting to survey para- 

 sites from poikilothermic and heterothermic hosts, in which such 

 variations are more likely to occur. 



The glycogen distribution in various organs and tissues has 

 been investigated both by quantitative chemical methods and 

 by differential staining. Toryu's (1933) analyses of various 

 organs of Parascaris equorum are summarized in the following 

 table: 



Organ 



Glycogen in percent of 



fresh substance total glycogen 



Body wall (cuticle + sub- 

 cuticle + muscles) 



Intestine 



Ovary 



Uterus - - 



Male reproductive system 



0.5 



The body wall is obviously the most important storage place 

 for glycogen in worms of both sexes. 



Differential glycogen staining has been used chiefly by v. 

 Kemnitz (1912) and ilartini (1916) working with Ascaris 

 and O.Tyuris, respectively. These workers extended the earlier 

 investigations of Brault and Loeper (1904) and Busch (1905). 

 It seems that in both cases the most intensive glycogen reac- 

 tions are found in the plasmatic bulbs of the muscle cells of 

 the body wall and in the hypodermis, cspeciall.v in the region 

 of the lateral chords, but it was also found in other organs, 

 for example, the intestine (compare also Hirsch and Bret- 

 schneider, 1937) and the reproductive organs. Glycogen, how- 

 ever, was never found in the cuticle, the phagocytic organs and 

 the nervous system. Additional data om the glycogen mor- 

 phology of other parasitic nematodes (Parascaris, Scleroslo- 

 mum, Helerakis and Ancylostoma) are found in the papers of 

 Busch (1905), V. Kemnitz (]912\ Faure Fremiet (1913), Tor- 

 yu (1933) and Giovaunola (1935). In these cases, the general 



360 



