178 The Pehrine Corpuscles in the Silkworm. 



parasite, in order to explain the phenomena. It should be stated 

 in this connection, that Beale considers the observations of both 

 Pouchet and Pasteur open to objections upon the ground of their 

 employment of very low powers. Many of the germs figured by 

 Beale were viewed with an objective of one-fiftieth of an inch focal 

 distance, enlarging the dimensions of these organisms 2800 dia- 

 meters. 



In such a field as this, speculation is illusory, and scientific 

 deductions are alone to be desired. Still the general trend of the 

 exposed strata is in one direction. They to whom the conservation 

 and transmutation of forces is an unalterable fact of physics, have 

 no difficulty in beUeving that there is a similar law to which the 

 vital forces are subject. Heat, light, and electricity are shown to 

 be modes of motion — interchangeable and intercurrent. The day 

 is, perhaps, not far distant, when it wiU be clear that contagious 

 and other diseases, which betray themselves by structural lesions, 

 depend upon the mode of motion of the bioplast. This motion is 

 known to be the measure of its energy. Can we not even declare 

 that it is the essential condition of its vitality ? Motionless bio- 

 plasm is dead. The transmutation of a normal to an abnormal 

 energy should, therefore, produce disease and ultimate death. If 

 this can be shown, it will be apparent that by an inversion of this 

 process restoration from disease occurs. 



Guerin-Meneville, in a report to the French Agricultural 

 Society in 1849 — mark the date ! — gives expression to the same 

 general thought. " It seems clear to me," said he, " that these 

 granules (pebrine corpuscles) are the elements of new blood- 

 globules, normally produced and launched into the vascular cur- 

 rents of healthy worms ; but in pathological conditions they lack 

 certain essential elements, and are therefore arrested in the pro- 

 gress of development," 



Pasteur describes the mature corpuscles as brilliant of refrac- 

 tion and ovoid in shape. They subsequently become pyriform, 

 surround themselves with a double envelope, and exhibit a slight 

 flattening at the narrower extremity. They contain granules, 

 either free or adherent to the cell-wall, and these, he believes, after 

 their exit by rupture of the cell-envelope, serve as new centres for 

 the development of new corpuscles, and thus extend the disease. 

 The tissue of these organisms was supposed to contain sarcode. 



7. Pebrine and syphilis are hereditary disorders. The 

 transmission of the disease of the silkworm from one generation 

 to another, has been the most fruitful source of evil in the pro- 

 pagation of the species. Unfortunately, before the microscope had 

 been employed in the study of the malady, sericulturists could not 

 be persuaded to believe that apparently healthy ova from parents 



