INORGANIC SUBSTANCES 



Ascaris lumbricoUIes according to Flury (1912) contains 0.76 

 percent inorganic substances, and a larval Etistrongi/lides ac- 

 cording to V. Brand (1938) contains 1.1 percent. 



A quantitative analysis of the inorganic substances of As- 

 caris by Flury (1912) gave the following results: 



Na - - — 1.104% of the dry weight 



K - 0.607 



Ca -- 0.404 



Mg 0.058 



Al -- -- 0.131 



Fe — 0.019 



CI 1-272 



PO4 -- 1-315 



SO. . - - 0.114 



SiO= 0.029 



Neither copper nor manganese was found, and it can be said 

 that on the whole the composition of the ash of Ascaris seems 

 to be quite similar to that of free living organisms. 



The osmotic pressure of the tissues of several Ascaris species 

 and that of the body fluid of Parascaris (Vialli, 1923, Schopfer, 

 1926, 1932) is similar, but not identical to that found in the 

 host intestine. The osmotic pressure of the worms always seems 

 to be a little lower, so that they live in a slightly hypertonic 

 environment. It is noteworthy that chlorides seem to play only 

 a minor role in producing the normal osmotic pressure of the 

 body fluid of Parascaris (Marcet, I86.1, Schopfer, 1932). The 

 total osmotic pressure corresponds to a freezing point depres- 

 sion (A) of — 0.62°C. wliercas the osmotic pressure due to the 

 chlorides is equivalent to a A value of — 0.12°C. The osmotic 

 pressure varies directly with that of the environment.' The 

 osmotic pressure of Frolcptiis obtusus living in the marine 

 elasmobranch ScuUiorhiiiiis is considerably higher than that 

 of the other parasites mentioned and is slightly higher than 

 that of Sci/lliorhiitiis blood (A = —2.40°, Schopfer, 1932). 



iPanikkar and Sproston (1941) give data for Angusticneeum sp. from 

 the intestine of the tortoise. It is of interest that according to Stoll 

 (1940) the first parasitic ecdysis of Hiiemnnclius contortus is favored 

 by hypotonic solutions. 



Metabolism of Adult Nematodes 



METABOLISM UNDER ANAEROBIC CONDITIONS 

 Most of the experiments on nematodes under anaerobic con- 

 ditions have been performed with Ascaris Uimbricoides. Bunge 

 (1889) found that this species can be kept for several days 

 in the absence of oxygen and that it produces during this time 

 carbon dioxide and a volatile acid. Considerable progress was 

 made by Weinland (1901) who performed quantitative deter- 

 minations of the amounts of various substances consumed and 

 produced and who recognized that carbohydrates were pre- 

 dominantly used. In starvation experiments of several days' 

 duration he found that 100 gm of worms consumed 0.7 gm 

 glycogen and 0.1 gm glucose in 24 hours. He found among the 

 end products 0.4 gm carbon dioxide and 0.3 gm of a volatile 

 fatty acid which he identified as valeric acid. Later Weinland 

 (1904) found that caproic acid was also present in the ether 

 soluble excreta of Ascaris. A quantitative study of fat and 

 nitrogen in similar starvation experiments led Weinland (1901) 

 to the conviction that both carbon dioxide and fatty acids were 

 derived from the breakdown of glycogen, and he compared this 

 process to the fermentations produced by microorganisms. This 

 view concerning the anaerobic processes of Ascaris is still valid, 

 although subsequent investigations necessitated certain changes 

 in Weinland 's conclusions. In the first place it was found that 

 in addition to valeric and caproic acids, some formic, butyric 

 (Flury, 1912) and lactic acid (v. Brand, 1934a) were also 

 present in the excreta. At present it is certain that valeric 

 acid is the chief end product, but there is some uncertainty as 

 to the type of valeric acid excreted. It seems probable that it 

 is normal valeric acid (Waechter, 1934), although Flury (1912) 

 believed that he had identified isovaleric acid. Kriiger (193(5) 

 suggested the presence of methyl-cthyl-acetie acid, but Oesterlin 

 (1937) pointed out that this identification was insulflciently 

 supported by Kriiger 's data. 



The second necessary modification of Weinland 's conclusions 

 concerns the intensity of the fermentation process. It was 

 found that with increasing length of starvation a deereising 

 daily amount of glycogen was used and that less carbon dia"ide 

 was produced (Weinland, 1901; Schulte, 1917; v. Brand, 19'i4a, 

 1937; Kriiger, 1936). In experiments conducted for only 24 

 hours' with fresh worms about 1.4 gm of glycogen was used. 

 This is twice as much as Weinland (1901) found for the av"n- 



age daily glycogen consumption (11.7 gm ) in experiments whicli 

 lasted as long as (i days. It is, however, curious and not yet 

 sufficiently understood, tliat despite the different lengths of 

 their experimental periods, most of the above mentioned in- 

 vestigators found that between 0.2 and 0.3 gm of valeric acid 

 was produced per day. Kriiger (1936), however, found that 

 about 0..5 gm fatty acid was excreted during the first 24 hours. 



The last complete biochemical balance under anaerobic condi- 

 tions was given by v. Brand (1934a) for females of Ascaris 

 hinihricoidcs. He found that 100 gm of worms consumed, dur- 

 ing 24 hours at 37°C., 1.39 gm glj'cogen and produced 0.71 gm 

 carbon dioxide, 0.22 gm valeric acid, and 0.02 gm of lactic 

 acid. No complete data are available for males. It has been 

 found, however, that the glycogen consumption is identical in 

 both sexes during the first 24 hours and that the more active 

 males later consume more glvcogen than the females (v. Brand, 

 1937a). 



Parascaris equorum seems to have a (piite similar carbohy- 

 drate metabolism. Fischer (1924) ascertained the production 

 of small amounts of lactic acid. Toryu (1936a) found a small 

 amount of lactic and propionic acid and a large amount of 

 valeric acid, but no formic, acetic, butyric, caproic, malic, citric 

 or succinic acids. His glycogen/acid balance for the first 24 

 hours of anaerobiosis for 100 gm of worms was as follows: 

 Consumed: 1.39 gm glycogen. Produced: 0.6."i gm valeric acid 

 and 0.02 gm lactic acid. In addition carbon dioxide was pro- 

 duced and the amount of carbon dioxide differed markedly for 

 females and males (Toryu, 19361)). It is not clear what ani- 

 mals were used for the glycogen/acid experiments, and there- 

 fore it is impossible to introduce leliable carlioii dioxide values 

 into the above balance. 



The above data indicate that the end jiroducts of the anaero- 

 bic carbohydrate metabolism are chiefly lower fatty acids and 

 therefore noticeably different from that of a vertebrate muscle. 

 This concept has been criticized chiefly by Fischer (1924) and 

 Slater (192-")). The former investigator concedes that living 

 Parascaris excrete only a small amount of lactic acid, and a 

 larger amount of an unidentified acid. He found, however, that 

 in minced material the i)roduction of lactic and the liberation 

 of phosphoric acid was sufficient to account for the whole 

 acidity oliscrved in aerobically conducted experiments. There- 

 fore, he concluded that there was no great difference between 

 the glycogen breakdown in Parascaris and in vertebrates. In 

 the opinion of the present writers, however, his observation in- 

 dicates merely that through changes in the experimental condi- 

 tions the course of the chemical reactions can be changed — a 

 phenomenon well known in e.xpcriments with yeast and other 

 lower plants. It should lie remembered that Weinland (1902) 

 found the same end products with extracts of Ascaris under 

 anaerobic conditions as he had found in experiments with 

 whole worms. 



Slater (1925) demonstrated that bacteria capable of trans- 

 forming sugar into volatile fatty acids could be isolated from 

 a saline solution in which ascarids had been immersed. He 

 failed, however, to show that the^' were present in sufficient 

 numbers to account for all the organic acids produced in ex- 

 periments with worms, and, furthermore, he did not demon- 

 strate any substance which could have served as a substrate for 

 such bacterial fermentation. 



Several lines of evidence have been brought forward which 

 seem to indicate a direct connection between nematodes and the 

 production of lower fattj' acids. The following two may be 

 mentioned. The volatile acids are found not only in saline in 

 which worms have been kept, but also in distillates of minced 

 worms (Weinland, 1901) and in the ether extract of whole 

 worms (Flury, 1912; Schimmelpfeunig, 1903). Valeric acid 

 has, furthermore, been found under both aerobic and anaerobic 

 conditions, although one should expect that such a difference in 

 the e.xternal conditions should have a deep influence on the 

 development of a bacterial flora in the surroundings. For fur- 

 ther information on this controversy compare the discussion of 

 Slater (1928) with those of Weinland (1901) and v. Brand 

 (1934b). 



Several methods have been discussed in which valeric acid 

 may originate from carbohydrate. Weinland (1901) favored 

 the" following equation: 4G,Hi20,, = 9C0= + SC^HioOi + 9H=. 

 It must, however, be emphasized, that the postulated hydrogen 

 could not be found. Weinland (1901) had to assume that it 

 was used at once in other reactions. He also discussed an equa- 

 tion proposed by Koenigs: 



13CoH,20„ = 12C=H,oO. + 18C0= + 18H:0. 



Weinland rejected this equation because it did not predict 

 nearly as much carbon dioxide as he found to be present. 

 However, the excess might have originated either from bicar- 

 bonate or from protein decomposition. Jost (1928) has given 

 the following chain of reactions which leads to Koenigs' equa- 



362 



