206 



THE AMERICAN MONTHLY 



[November, 



drical cavity running lengthwise, like 

 a wide oscular tube. Tubes open be- 

 low into a system of anastomosing la- 

 cunce. Dermis is rich in pores. In the 

 mesoderm there is a band of mem- 

 branous tissue, which runs from the 

 outer surface toward the interior. It 

 is of uniform thickness throughout. 

 Cells run out at each end to extremely 

 fine points, .i mm. X -003 mm. These 

 have an oval nucleus about their mid- 

 dle and on one side of the axis. Near 

 the nucleus is a small quantity of or- 

 dinary protoplasm, while all the rest 

 of the cell consists of a substance 

 which differs essentially from the con- 

 tents of ordinary fusiform cells. It con- 

 tains small, distinct, strong, doublv 

 refractile granules imbedded in a ho- 

 mogeneous transparent substance 

 which is slightly but simply refractile. 

 Granules are, in fact, regularly ar- 

 ranged, so that a sort of transverse stri- 

 ation of the fibres is produced. These 

 bands are strongly contractile, and 

 contract in a radial direction. The 

 author concludes from this observation 

 that the membranes are muscles, and. 

 further, that these muscle cells are to 

 be regarded as a form transitional be- 

 tween the smooth and striped muscle 

 cells. 



In transverse sections through the 

 margins of the groove there is to be 

 seen a peculiar organ seated upon the 

 upper and outer margin of the mus- 

 cular membrane. The membrane is 

 suddenly increased to twice or three 

 times its diameter elsewhere. This 

 line of thickening is seen in sections 

 not to consist of fusiform cells, but of 

 large, globular, very distinct nuclei, 

 imbedded in a granular substance no 

 doubt belonging to the cells whose 

 boundaries are indistinct. From the 

 marginal thickenings threads issue 

 laterally and run tangentially in the ex- 

 terior deimiis of the sponge, and may be 

 traced a considerable distance. Above 

 and on these destal thickenings there 

 stand fusiform sense-cells. Their ba- 

 sal ends, diffused over a broad zone, 

 are in direct connection with the thick- 

 enings ; no ramification of basal pro- 



cesses was observed. The cell body 

 has the ordinary form, .03 mm. X 

 .002 mm., broadest in the middle. 

 In the cell body, after treatment with 

 osmic acid, there are found dark gran- 

 ules like those characteristic of Hydra 

 (Jickeli). 



The author's interpretation of these 

 obsei"vations is as follows : — 



The vs^hole thickening is composed 

 of ganglion cells, whose contours are 

 not distinct, and the granular threads, 

 leading from them are nerve fibres. 

 They mav be compared with the an- 

 nular nerve-ring of Cycloneural me- 

 dusce (Eimer), and indicate that the 

 sponges, being capable of a develop- 

 ment similar to that of the Cuidaria, 

 were probably not so different from 

 them as we commonly suppose. We 

 must, however, bear in mind that the 

 muscle and nerve are not sub-epi- 

 thelial but mesodermal. 



The Bacillus of Malaria. 



[From the Lancet for Aug. 21, 1886; copied from 

 Journ. Am. Med. Assoc. Oct. 2, '86.] 



In 1879 Professor Tom masi-Crudeli 

 published in the Atti della Reale Ac- 

 cademia dei Lincei, at Rome, a me- 

 moir on the distribution of the subsoil 

 water of the Roman Campagna, and 

 on its influence in the production of 

 malaria. In this research, which 

 proved the starting-point of new 

 studies on the etiology of malaria, the 

 author traced the origin of this mor- 

 bigenous ferment, discarding many 

 errors and prejudices of old medicine 

 and maintaining that the causal agent 

 of the disease could only be a living 

 organism. 



Towards the close of the same year 

 Tommasi-Crudeli and Klebs pub- 

 lished in the same Atti a memoir 

 embodying the results of inquiries on 

 malaric airs and soils, and of experi- 

 ments on rabbits, proving that the 

 living organism is a schizomycete, 

 named by them Bacillus malarice. 

 As the result of researches on the in- 

 dividuals affected with malaria, Mar- 

 chiafava and Celli announced that 

 within the red-blood globules are con- 



