The development of crescentic, ovoid, or fusiform bodies and the significance of their association with mstivo-autumnal infections have already been referred to. These bodies are not likely to be observed in the blood until the fever has lasted for a week or more; they may persist, how ; ever, for several weeks after other forms of the parasite have disappeared. The intracorpuscular origin of crescents has been proved by Marchiafava and Celli 1 and confirmed by many others, and, as stated, they result from the transforma tion of intracorpuscular spherical forms of mstivo-autumnal parasites, which at this point fail to continue their orderly cycle of development. Except rarely, only fully-developed crescents are ob i served in the circulating blood, the early I stages of intracorpuscular development taking place in the spleen and, especially, the bone-marrow. They are always pig mented, and the pigment, which is very ; dark in color and usually in fine rods or I granules, is without movement and is k collected in one or two masses near the , middle of the organism. In crescents that are not fully developed the pigment is less regularly disposed. From cres cents flagellate bodies may develop, but only from the round bodies of the group.
[According to the view entertained by Mannaberg, crescents are to be regarded as encysted syzygies produced by the conjugation of two parasites (cestivo autumnal) and therefore capable of seg mentation and reproduction. This, how ever, is not the generally-accepted hy pothesis regarding the significance of these bodies. The majority of observers hold to. the view that, in the human body at least, they exist as sterile forms, and, if they possess any reproductive faculty, require for its accomplishment some favorable extracorpuscular environment. Bignarni and Bastianelli (Lancet, Dec. '98), in their latest contribution to this subject, arrive at these conclusions: "We have, indeed, favored the idea that the semilunar bodies are sterile on the grounds that one -never sees in them any form of multiplication and that they have no relation to relapses; and these assertions, even in the light of these new observations, we still hold by as in ac cordance with the truth. In other words, we contended that crescents are sterile bodies in man and as far as man is C011 cerned. In fact, we put forward the ad ditional hypothesis that these bodies rep resent those phases of the life of the malarial parasite which in other para sites are continued and completed out side of the host. Should such migration from the host fail to occur, then that phase of life which cannot be completed except in the outside world or in a new host will be carried out in an abortive way and will terminate in forms of de generation.
"Certainly these new researches render probable the hypothesis that the cycle commenced in the blood of man is com pleted in some species of mosquito, but they nevertheless do not negate the truth of the fact alluded to in our first lic,rpothe sis in those cases where the passage from man to the new host fails to take place."
,T.AmEs C. WILSON and THOMAS G. ASH TON.] Flagellation is an occurrence common to each of the three principal varieties of parasites. It is to be observed within minutts after the blood _ 1r,iwn from the body and 4 ti.ur •11 the circulating blood.
0.iittd out, in xstivo-au ,.,:..•,. .24:t 11011 deVelOp - N 111 Ille spherical form of the cres - •,- .111), 1111110 ill tertian and guar ! ii.,ns their origin is from the f.-1 .k.,rdwn extracorpuseular organisms. Icrztlf of the flagella varies from the d'aineter of a red blood ( rviics. le to an extent three or four times Their number may vary from 112 to and their attachment may be D. any portion of the circumference of 1 ody. Free. detached flagella may a',0 be observed. As may be surmised, the active movements of the flagella pro diyeo, a marked disturbance of the blood c4r1 Undkr ordinary circumstances flagel I It. d plasmodia do not appear in a, speei f en of blood until some time after it has I ern removed from the body, generally from fifteen to twenty minutes. The foi 1 ,..ing method of obtaining these bodies i- at once simple and effective: The l'[.7(r or ear is carefully cleansed with alcohol, as are also the slides and cover ulasses. A small elastie band is now laced around the finger, or, if the lobe f the ear is used, it is compressed by an assistant. The puncture is made with a -terile needle or lancet and the first drop of blood w iped away. A second dr, p is now squeezed out and allowed t remain exposed to the air until the -Ude is breathed gently upon by the .perator, when the tip of the drop of b.-6d is gently pressed upon the surface ••f the slide which has been breathed fq.c.n. The cover-glass is then immedi tely laced over it, and the preparation i- red ly to examine. The slight exposure to the air, and the small amount of moisture upon the slide caused •hy Ireathing upon it, seem to hasten ex flagellation, for specimens so prepared ahn .e-t invariably contain flagellated bodies. C. F. Craig (N. Y. Med. Jour., Dee. 23, '99..
According to Manson, flagella consti tute the first phases of the malarial para site outside of man, and they represent parasites in sporulation the spores of which take on this special form of mobile and flagellated filaments "in the interest of the extracorporeal life of tile plas modium." Much the sante view is en tertained by Mannaberg, who believes that they represent a phase of the sa prophytic existence of the parasite. Re garding their internal structure we possess no knowledge other than that imparted by Sacharoff, who considers the flagella as chromosomes originating in the nuclei of the body of the parasite, while the flagellation he regards as a process of perverted karyokinetic divis ion accomplished in a violent manner.