295 



Wasser (in manchen Fällen durch Wasser mit 0,3 Procent Chlor- 

 natrium) ersetzen. 



Auch darf man nicht unbeachtet lassen, daß die Anwesenheit von 

 unzersetztem Wasserstoff- Superoxyd viele Farbstoffe, Überosmium- 

 säure und andere Reagentien in ihren Wirkungen beeinträchtigen 

 kann. 



Nach der Entfernung des überschüssigen Superoxyds kann man 

 eine der bekannten und für den Fall passenden Conservierungs-Me- 

 thoden wählen , denn zum Conservieren mikroskopischer Praeparate 

 eignet sich unser Mittel nicht. 



Weil die käuflichen Wasserstoff-Superoxydlösungen wohl immer 

 geringe Mengen freier Mineralsäuren enthalten und darum nicht ver- 

 wendbar sind, wenn es sich um Objecte handelt, bei welchen Calcium- 

 carbonat zu berücksichtigen ist, habe ich mir eine säurefreie Lösung 

 selbst dargestellt. Solche Lösungen halten sich indessen nur dann 

 einige Zeit, wenn man sie in kleinen damit vollgefüllten braunen 

 Glasstöpselfläschchen im Keller, also vor Licht und Wärme geschützt, 

 aufbewahrt. 



Eatzeburg, den 15. Mai 1896. 



2. The Academy of Natural Sciences of Philadelphia. 



May 5th, 1896. — Dr. F. P. Henry made a communication on i^tAïna 

 sanguinis hominis nocturna , specimens of which had been obtained from the 

 blood of a patient suffering from chyluria due to clogging of the lymphatics 

 by the ova of the parasite. The various forms of the worm with their life- 

 history as given by Dr. Patrick Hanson were dwelt on. The parasite secre- 

 tes no toxine and its presence in man is usually not productive of bad effects. 

 The speaker stated his belief that the excretory products of the parasites are 

 hurtfiil to man in proportion to the lowness of their organisation. The 

 nocturnal Filariae appear in the superficial vessels about sunset and disappear 

 about the time of rising. In patients induced to sleep during the day the 

 periodicity is reversed. The only treatment is prophylactic as a drug which 

 would kill the mature worm would, in all probability, be hurtful to the host 

 by causing abscesses around the dead product. — Dr. Leonard, m conti- 

 nuation, dwelt on the morphology of the worm illustrating his remarks by 

 means of fine microphotographs of the specimens described by Dr. Henry. 



May 12th, 1896. —Dr. Charles S. Dolley described a centrifrugal appa- 

 ratus for the quantitative determination of the food supply of oysters and other 

 aquatic animals which he called Planktonokrit. By means of its use he is 

 enabled to make a large number of plankton estimates in a day and thus judge 

 of the characters of given areas of water in connection with fish and oyster 

 culture at different times of the day, states of the tide, varying depths, etc. 

 The method employed is that of the centrifuge, an apparatus which consists 

 of a series of geared wheels driven by hand or belt and so arranged as to 

 cause an upright shaft to revolve up to a speed of 8000 revolutions per 

 minute, corresponding to 50 revolutions per minute of the crank or pulley 

 wheel. To this upright shaft is fastened an attachment by means of which 



