44 INANITION AND MALNUTRITION 



"Beachtet man, dass die postembryonale Entwicklung der Geschlechts- 

 organe in der Reihenfolge vor sich geht, dass zuerst die Bildung der Ovarien 

 und Hoden, viel spater erst die Entwicklung des Begattungsapparates und am 

 Schluss die Anlage der Dotterstocke erfolgt, so findet man, dass die Involution 

 der Geschlechtsorgane in der umgekehrte Reihenfolge stattjlndet, wie ihre Entstehung." 



Berninger ('n) likewise studied the effects of inanition in various species of 

 planarians (Planaria alpina, gonocephala, torva; Polycelis nigra; Dendrocoelum 

 lacteum), with results in general agreement with those of Stoppenbrink, Schultz 

 and other earlier investigators. Death from starvation occurs in six to twelve 

 months, with length reduced to about 3-12 5 volume to ^300- The nervous and 

 muscular systems suffer no actual degeneration; the gut and "parenchyma" 

 (stroma) but little. In darkness, the eyes degenerate and are entirely resorbed 

 in seven or eight months. Of the reproductive system, the vitelline glands and 

 penis are resorbed first, then the genital passages, later the ovaries and lastly 

 (just before death) the testes. The "cocoons" are dwarfed and the enclosed 

 embryos reduced in size and number. Regeneration of the sex-organs is possible 

 upon refeeding, even when they have almost disappeared after three or four 

 months of fasting. 



Lang ('12) in connection with a study of regeneration in planarians, was 

 able to confirm in general the results of previous investigators as to the effects 

 of inanition. "Exkretionsgefasssystem, Muskulatur und Nervensystem blei- 

 ben nicht nur vor dem Zerfall verschont, sondern regenerieren auch noch 

 abgeschnittene Teile. Insbesondere regeneriert sich im Verlauf der Langs- 

 nerven stamme an Querschnitten ein neues Gehirn. Bei den gesamten 

 Reduktionen und Regenerationen werden diejenigen Organe verschont bezw. 

 gefordert die entweder zum Leben des Individuums unbedingt notig sind oder 

 die eine Vorbedingung fur Beseitigung des Hungerzustandes bedeuten, 

 insbesondere Pharynx und Nervensystem." 



In connection with a series of physiological studies, based upon experiments 

 with planarians (chiefly Planaria dorotocephala), Child ('11, '15, '19, '20) has 

 made incidental observations as to the morphological effects of inanition. Accord- 

 ing to his conception, age is characterized physiologically by decreased metabo- 

 lism, expressed morphologically by accumulation of structures which hinder 

 cell-metabolism. "Starvation removes the structural obstacles to a greater or 

 less extent, but without increasing the rate of metabolism, except perhaps at 

 first; by means of food the rate of metabolism is increased and rejuvenation is 

 accomplished. Starvation brings about morphological rejuvenation, the 

 following feeding, physiological regeneration." 



In connection with his experiments on partial inanition with various salt 

 deficiencies, Herbst ('97) made some incidental observations upon the marine 

 polyclad worms, Stylochus neapolitanus, Discocoelis tigrina and Thysanozoon 

 Brochii. In solutions without calcium phosphate, they died and disintegrated 

 within about eighteen hours (controls unaffected), thus indicating the necessity 

 for this salt in the medium for adult polyclads. 



Nemertinea. — Aside from the observations by Giard ('05) onLineus bilineatus, 

 the effects of inanition upon the nemertin worms have been studied by Nus- 



